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Software / API Bindings / Go / API Reference and Examples / Bricklets / RS485 Bricklet

Go - RS485 Bricklet

This is the description of the Go API bindings for the RS485 Bricklet. General information and technical specifications for the RS485 Bricklet are summarized in its hardware description.

An installation guide for the Go API bindings is part of their general description. Additional documentation can be found on godoc.org.

Examples

The example code below is Public Domain (CC0 1.0).

Loopback

Download (example_loopback.go)

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package main

import (
    "fmt"
    "github.com/Tinkerforge/go-api-bindings/ipconnection"
    "github.com/Tinkerforge/go-api-bindings/rs485_bricklet"
)

// For this example connect the RX+/- pins to TX+/- pins on the same Bricklet
// and configure the DIP switch on the Bricklet to full-duplex mode

const ADDR string = "localhost:4223"
const UID string = "XYZ" // Change XYZ to the UID of your RS485 Bricklet.

func main() {
    ipcon := ipconnection.New()
    defer ipcon.Close()
    rs485, _ := rs485_bricklet.New(UID, &ipcon) // Create device object.

    ipcon.Connect(ADDR) // Connect to brickd.
    defer ipcon.Disconnect()
    // Don't use device before ipcon is connected.

    // Enable full-duplex mode
    rs485.SetRS485Configuration(115200, rs485_bricklet.ParityNone,
        rs485_bricklet.Stopbits1, rs485_bricklet.Wordlength8,
        rs485_bricklet.DuplexFull)

    rs485.RegisterReadCallback(func(message []rune) {
        fmt.Println(string(message))
    })

    // Enable read callback
    rs485.EnableReadCallback()

    rs485.Write([]rune{'t', 'e', 's', 't'})

    fmt.Print("Press enter to exit.")
    fmt.Scanln()
}

Modbus Slave

Download (example_modbus_slave.go)

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package main

import (
    "fmt"
    "github.com/Tinkerforge/go-api-bindings/ipconnection"
    "github.com/Tinkerforge/go-api-bindings/rs485_bricklet"
)

const ADDR string = "localhost:4223"
const UID string = "XYZ" // Change XYZ to the UID of your RS485 Bricklet.

func main() {
    ipcon := ipconnection.New()
    defer ipcon.Close()
    rs485, _ := rs485_bricklet.New(UID, &ipcon) // Create device object.

    ipcon.Connect(ADDR) // Connect to brickd.
    defer ipcon.Disconnect()
    // Don't use device before ipcon is connected.

    // Set operating mode to Modbus RTU slave
    rs485.SetMode(rs485_bricklet.ModeModbusSlaveRTU)

    // Modbus specific configuration:
    // - slave address = 17
    // - master request timeout = 0ms (unused in slave mode)
    rs485.SetModbusConfiguration(17, 0)

    rs485.RegisterModbusSlaveWriteSingleRegisterRequestCallback(func(requestID uint8, registerAddress uint32, registerValue uint16) {
        fmt.Println("Request ID: ", requestID)
        fmt.Println("Register Address: ", registerAddress)
        fmt.Println("Register Value: ", registerValue)
        if registerAddress != 42 {
            fmt.Println("Error: Invalid register address")
            rs485.ModbusSlaveReportException(requestID, rs485_bricklet.ExceptionCodeIllegalDataAddress)
        } else {
            rs485.ModbusSlaveAnswerWriteSingleRegisterRequest(requestID)
        }
    })

    fmt.Print("Press enter to exit.")
    fmt.Scanln()
}

Modbus Master

Download (example_modbus_master.go)

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package main

import (
    "fmt"
    "github.com/Tinkerforge/go-api-bindings/ipconnection"
    "github.com/Tinkerforge/go-api-bindings/rs485_bricklet"
)

const ADDR string = "localhost:4223"
const UID string = "XYZ" // Change XYZ to the UID of your RS485 Bricklet.

func main() {
    ipcon := ipconnection.New()
    defer ipcon.Close()
    rs485, _ := rs485_bricklet.New(UID, &ipcon) // Create device object.

    ipcon.Connect(ADDR) // Connect to brickd.
    defer ipcon.Disconnect()
    // Don't use device before ipcon is connected.

    // Set operating mode to Modbus RTU master
    rs485.SetMode(rs485_bricklet.ModeModbusMasterRTU)

    // Modbus specific configuration:
    // - slave address = 1 (unused in master mode)
    // - master request timeout = 1000ms
    rs485.SetModbusConfiguration(1, 1000)

    expectedRequestID := uint8(0)

    rs485.RegisterModbusMasterWriteSingleRegisterResponseCallback(func(requestID uint8, exceptionCode rs485_bricklet.ExceptionCode) {
        fmt.Printf("Request ID: %d\n", requestID)

        if exceptionCode == rs485_bricklet.ExceptionCodeTimeout {
            fmt.Println("Exception Code: Timeout")
        } else if exceptionCode == rs485_bricklet.ExceptionCodeSuccess {
            fmt.Println("Exception Code: Success")
        } else if exceptionCode == rs485_bricklet.ExceptionCodeIllegalFunction {
            fmt.Println("Exception Code: Illegal Function")
        } else if exceptionCode == rs485_bricklet.ExceptionCodeIllegalDataAddress {
            fmt.Println("Exception Code: Illegal Data Address")
        } else if exceptionCode == rs485_bricklet.ExceptionCodeIllegalDataValue {
            fmt.Println("Exception Code: Illegal Data Value")
        } else if exceptionCode == rs485_bricklet.ExceptionCodeSlaveDeviceFailure {
            fmt.Println("Exception Code: Slave Device Failure")
        } else if exceptionCode == rs485_bricklet.ExceptionCodeAcknowledge {
            fmt.Println("Exception Code: Acknowledge")
        } else if exceptionCode == rs485_bricklet.ExceptionCodeSlaveDeviceBusy {
            fmt.Println("Exception Code: Slave Device Busy")
        } else if exceptionCode == rs485_bricklet.ExceptionCodeMemoryParityError {
            fmt.Println("Exception Code: Memory Parity Error")
        } else if exceptionCode == rs485_bricklet.ExceptionCodeGatewayPathUnavailable {
            fmt.Println("Exception Code: Gateway Path Unavailable")
        } else if exceptionCode == rs485_bricklet.ExceptionCodeGatewayTargetDeviceFailedToRespond {
            fmt.Println("Exception Code: Gateway Target Device Failed To Respond")
        }
        if requestID != expectedRequestID {
            fmt.Println("Error: Unexpected request ID")
        }
    })

    // Write 65535 to register 42 of slave 17
    expectedRequestID, _ = rs485.ModbusMasterWriteSingleRegister(17, 42, 65535)

    fmt.Print("Press enter to exit.")
    fmt.Scanln()
}

API

The RS485 Bricklet API is defined in the package github.com/Tinkerforge/go-api-bindings/rs485_bricklet

Nearly every function of the Go bindings can return an ipconnection.DeviceError, implementing the error interface. The error can have one of the following values:

  • ipconnection.DeviceErrorSuccess = 0
  • ipconnection.DeviceErrorInvalidParameter = 1
  • ipconnection.DeviceErrorFunctionNotSupported = 2
  • ipconnection.DeviceErrorUnknownError = 3

which correspond to the values returned from Bricks and Bricklets.

All functions listed below are thread-safe.

Basic Functions

func rs485_bricklet.New(uid string, ipcon *IPConnection) (device RS485Bricklet, err error)
Parameters:
  • uid – Type: string
  • ipcon – Type: *IPConnection
Returns:
  • device – Type: RS485Bricklet
  • err – Type: error

Creates a new RS485Bricklet object with the unique device ID uid and adds it to the IPConnection ipcon:

device, err := rs485_bricklet.New("YOUR_DEVICE_UID", &ipcon)

This device object can be used after the IPConnection has been connected.

func (*RS485Bricklet) Write(message []rune) (messageChunkWritten uint64, err error)
Parameters:
  • message – Type: []rune, Length: variable
Returns:
  • messageWritten – Type: uint16, Range: [0 to 216 - 1]
  • err – Type: error

Writes characters to the RS485 interface. The characters can be binary data, ASCII or similar is not necessary.

The return value is the number of characters that were written.

See SetRS485Configuration() for configuration possibilities regarding baudrate, parity and so on.

func (*RS485Bricklet) Read(length uint16) (message []rune, err error)
Parameters:
  • length – Type: uint16, Range: [0 to 216 - 1]
Returns:
  • message – Type: []rune, Length: variable
  • err – Type: error

Returns up to length characters from receive buffer.

Instead of polling with this function, you can also use callbacks. But note that this function will return available data only when the read callback is disabled. See EnableReadCallback() and ReadCallback callback.

func (*RS485Bricklet) SetRS485Configuration(baudrate uint32, parity uint8, stopbits uint8, wordlength uint8, duplex uint8) (err error)
Parameters:
  • baudrate – Type: uint32, Unit: 1 Bd, Range: [100 to 2000000], Default: 115200
  • parity – Type: uint8, Range: See constants, Default: 0
  • stopbits – Type: uint8, Range: See constants, Default: 1
  • wordlength – Type: uint8, Range: See constants, Default: 8
  • duplex – Type: uint8, Range: See constants, Default: 0
Returns:
  • err – Type: error

Sets the configuration for the RS485 communication.

The following constants are available for this function:

For parity:

  • rs485_bricklet.ParityNone = 0
  • rs485_bricklet.ParityOdd = 1
  • rs485_bricklet.ParityEven = 2

For stopbits:

  • rs485_bricklet.Stopbits1 = 1
  • rs485_bricklet.Stopbits2 = 2

For wordlength:

  • rs485_bricklet.Wordlength5 = 5
  • rs485_bricklet.Wordlength6 = 6
  • rs485_bricklet.Wordlength7 = 7
  • rs485_bricklet.Wordlength8 = 8

For duplex:

  • rs485_bricklet.DuplexHalf = 0
  • rs485_bricklet.DuplexFull = 1
func (*RS485Bricklet) GetRS485Configuration() (baudrate uint32, parity uint8, stopbits uint8, wordlength uint8, duplex uint8, err error)
Returns:
  • baudrate – Type: uint32, Unit: 1 Bd, Range: [100 to 2000000], Default: 115200
  • parity – Type: uint8, Range: See constants, Default: 0
  • stopbits – Type: uint8, Range: See constants, Default: 1
  • wordlength – Type: uint8, Range: See constants, Default: 8
  • duplex – Type: uint8, Range: See constants, Default: 0
  • err – Type: error

Returns the configuration as set by SetRS485Configuration().

The following constants are available for this function:

For parity:

  • rs485_bricklet.ParityNone = 0
  • rs485_bricklet.ParityOdd = 1
  • rs485_bricklet.ParityEven = 2

For stopbits:

  • rs485_bricklet.Stopbits1 = 1
  • rs485_bricklet.Stopbits2 = 2

For wordlength:

  • rs485_bricklet.Wordlength5 = 5
  • rs485_bricklet.Wordlength6 = 6
  • rs485_bricklet.Wordlength7 = 7
  • rs485_bricklet.Wordlength8 = 8

For duplex:

  • rs485_bricklet.DuplexHalf = 0
  • rs485_bricklet.DuplexFull = 1
func (*RS485Bricklet) SetModbusConfiguration(slaveAddress uint8, masterRequestTimeout uint32) (err error)
Parameters:
  • slaveAddress – Type: uint8, Range: [1 to 247], Default: 1
  • masterRequestTimeout – Type: uint32, Unit: 1 ms, Range: [0 to 232 - 1], Default: 1000
Returns:
  • err – Type: error

Sets the configuration for the RS485 Modbus communication. Available options:

  • Slave Address: Address to be used as the Modbus slave address in Modbus slave mode. Valid Modbus slave address range is 1 to 247.
  • Master Request Timeout: Specifies how long the master should wait for a response from a slave when in Modbus master mode.
func (*RS485Bricklet) GetModbusConfiguration() (slaveAddress uint8, masterRequestTimeout uint32, err error)
Returns:
  • slaveAddress – Type: uint8, Range: [1 to 247], Default: 1
  • masterRequestTimeout – Type: uint32, Unit: 1 ms, Range: [0 to 232 - 1], Default: 1000
  • err – Type: error

Returns the configuration as set by SetModbusConfiguration().

func (*RS485Bricklet) SetMode(mode uint8) (err error)
Parameters:
  • mode – Type: uint8, Range: See constants, Default: 0
Returns:
  • err – Type: error

Sets the mode of the Bricklet in which it operates. Available options are

  • RS485,
  • Modbus Master RTU and
  • Modbus Slave RTU.

The following constants are available for this function:

For mode:

  • rs485_bricklet.ModeRS485 = 0
  • rs485_bricklet.ModeModbusMasterRTU = 1
  • rs485_bricklet.ModeModbusSlaveRTU = 2
func (*RS485Bricklet) GetMode() (mode uint8, err error)
Returns:
  • mode – Type: uint8, Range: See constants, Default: 0
  • err – Type: error

Returns the configuration as set by SetMode().

The following constants are available for this function:

For mode:

  • rs485_bricklet.ModeRS485 = 0
  • rs485_bricklet.ModeModbusMasterRTU = 1
  • rs485_bricklet.ModeModbusSlaveRTU = 2

Advanced Functions

func (*RS485Bricklet) SetCommunicationLEDConfig(config uint8) (err error)
Parameters:
  • config – Type: uint8, Range: See constants, Default: 3
Returns:
  • err – Type: error

Sets the communication LED configuration. By default the LED shows RS485 communication traffic by flickering.

You can also turn the LED permanently on/off or show a heartbeat.

If the Bricklet is in bootloader mode, the LED is off.

The following constants are available for this function:

For config:

  • rs485_bricklet.CommunicationLEDConfigOff = 0
  • rs485_bricklet.CommunicationLEDConfigOn = 1
  • rs485_bricklet.CommunicationLEDConfigShowHeartbeat = 2
  • rs485_bricklet.CommunicationLEDConfigShowCommunication = 3
func (*RS485Bricklet) GetCommunicationLEDConfig() (config uint8, err error)
Returns:
  • config – Type: uint8, Range: See constants, Default: 3
  • err – Type: error

Returns the configuration as set by SetCommunicationLEDConfig()

The following constants are available for this function:

For config:

  • rs485_bricklet.CommunicationLEDConfigOff = 0
  • rs485_bricklet.CommunicationLEDConfigOn = 1
  • rs485_bricklet.CommunicationLEDConfigShowHeartbeat = 2
  • rs485_bricklet.CommunicationLEDConfigShowCommunication = 3
func (*RS485Bricklet) SetErrorLEDConfig(config uint8) (err error)
Parameters:
  • config – Type: uint8, Range: See constants, Default: 3
Returns:
  • err – Type: error

Sets the error LED configuration.

By default the error LED turns on if there is any error (see ErrorCountCallback callback). If you call this function with the SHOW ERROR option again, the LED will turn off until the next error occurs.

You can also turn the LED permanently on/off or show a heartbeat.

If the Bricklet is in bootloader mode, the LED is off.

The following constants are available for this function:

For config:

  • rs485_bricklet.ErrorLEDConfigOff = 0
  • rs485_bricklet.ErrorLEDConfigOn = 1
  • rs485_bricklet.ErrorLEDConfigShowHeartbeat = 2
  • rs485_bricklet.ErrorLEDConfigShowError = 3
func (*RS485Bricklet) GetErrorLEDConfig() (config uint8, err error)
Returns:
  • config – Type: uint8, Range: See constants, Default: 3
  • err – Type: error

Returns the configuration as set by SetErrorLEDConfig().

The following constants are available for this function:

For config:

  • rs485_bricklet.ErrorLEDConfigOff = 0
  • rs485_bricklet.ErrorLEDConfigOn = 1
  • rs485_bricklet.ErrorLEDConfigShowHeartbeat = 2
  • rs485_bricklet.ErrorLEDConfigShowError = 3
func (*RS485Bricklet) SetBufferConfig(sendBufferSize uint16, receiveBufferSize uint16) (err error)
Parameters:
  • sendBufferSize – Type: uint16, Unit: 1 B, Range: [210 to 9216], Default: 5120
  • receiveBufferSize – Type: uint16, Unit: 1 B, Range: [210 to 9216], Default: 5120
Returns:
  • err – Type: error

Sets the send and receive buffer size in byte. In sum there is 10240 byte (10KiB) buffer available and the minimum buffer size is 1024 byte (1KiB) for both.

The current buffer content is lost if this function is called.

The send buffer holds data that was given by Write() and could not be written yet. The receive buffer holds data that is received through RS485 but could not yet be send to the user, either by Read() or through ReadCallback callback.

func (*RS485Bricklet) GetBufferConfig() (sendBufferSize uint16, receiveBufferSize uint16, err error)
Returns:
  • sendBufferSize – Type: uint16, Unit: 1 B, Range: [210 to 9216], Default: 5120
  • receiveBufferSize – Type: uint16, Unit: 1 B, Range: [210 to 9216], Default: 5120
  • err – Type: error

Returns the buffer configuration as set by SetBufferConfig().

func (*RS485Bricklet) GetBufferStatus() (sendBufferUsed uint16, receiveBufferUsed uint16, err error)
Returns:
  • sendBufferUsed – Type: uint16, Unit: 1 B, Range: [0 to 9216]
  • receiveBufferUsed – Type: uint16, Unit: 1 B, Range: [0 to 9216]
  • err – Type: error

Returns the currently used bytes for the send and received buffer.

See SetBufferConfig() for buffer size configuration.

func (*RS485Bricklet) GetErrorCount() (overrunErrorCount uint32, parityErrorCount uint32, err error)
Returns:
  • overrunErrorCount – Type: uint32, Range: [0 to 232 - 1]
  • parityErrorCount – Type: uint32, Range: [0 to 232 - 1]
  • err – Type: error

Returns the current number of overrun and parity errors.

func (*RS485Bricklet) GetModbusCommonErrorCount() (timeoutErrorCount uint32, checksumErrorCount uint32, frameTooBigErrorCount uint32, illegalFunctionErrorCount uint32, illegalDataAddressErrorCount uint32, illegalDataValueErrorCount uint32, slaveDeviceFailureErrorCount uint32, err error)
Returns:
  • timeoutErrorCount – Type: uint32, Range: [0 to 232 - 1]
  • checksumErrorCount – Type: uint32, Range: [0 to 232 - 1]
  • frameTooBigErrorCount – Type: uint32, Range: [0 to 232 - 1]
  • illegalFunctionErrorCount – Type: uint32, Range: [0 to 232 - 1]
  • illegalDataAddressErrorCount – Type: uint32, Range: [0 to 232 - 1]
  • illegalDataValueErrorCount – Type: uint32, Range: [0 to 232 - 1]
  • slaveDeviceFailureErrorCount – Type: uint32, Range: [0 to 232 - 1]
  • err – Type: error

Returns the current number of errors occurred in Modbus mode.

  • Timeout Error Count: Number of timeouts occurred.
  • Checksum Error Count: Number of failures due to Modbus frame CRC16 checksum mismatch.
  • Frame Too Big Error Count: Number of times frames were rejected because they exceeded maximum Modbus frame size which is 256 bytes.
  • Illegal Function Error Count: Number of errors when an unimplemented or illegal function is requested. This corresponds to Modbus exception code 1.
  • Illegal Data Address Error Count: Number of errors due to invalid data address. This corresponds to Modbus exception code 2.
  • Illegal Data Value Error Count: Number of errors due to invalid data value. This corresponds to Modbus exception code 3.
  • Slave Device Failure Error Count: Number of errors occurred on the slave device which were unrecoverable. This corresponds to Modbus exception code 4.
func (*RS485Bricklet) ModbusSlaveReportException(requestID uint8, exceptionCode int8) (err error)
Parameters:
  • requestID – Type: uint8, Range: [0 to 255]
  • exceptionCode – Type: int8, Range: See constants
Returns:
  • err – Type: error

In Modbus slave mode this function can be used to report a Modbus exception for a Modbus master request.

  • Request ID: Request ID of the request received by the slave.
  • Exception Code: Modbus exception code to report to the Modbus master.

The following constants are available for this function:

For exceptionCode:

  • rs485_bricklet.ExceptionCodeTimeout = -1
  • rs485_bricklet.ExceptionCodeSuccess = 0
  • rs485_bricklet.ExceptionCodeIllegalFunction = 1
  • rs485_bricklet.ExceptionCodeIllegalDataAddress = 2
  • rs485_bricklet.ExceptionCodeIllegalDataValue = 3
  • rs485_bricklet.ExceptionCodeSlaveDeviceFailure = 4
  • rs485_bricklet.ExceptionCodeAcknowledge = 5
  • rs485_bricklet.ExceptionCodeSlaveDeviceBusy = 6
  • rs485_bricklet.ExceptionCodeMemoryParityError = 8
  • rs485_bricklet.ExceptionCodeGatewayPathUnavailable = 10
  • rs485_bricklet.ExceptionCodeGatewayTargetDeviceFailedToRespond = 11
func (*RS485Bricklet) ModbusSlaveAnswerReadCoilsRequest(requestID uint8, coils []bool) (err error)
Parameters:
  • requestID – Type: uint8, Range: [0 to 255]
  • coils – Type: []bool, Length: variable
Returns:
  • err – Type: error

In Modbus slave mode this function can be used to answer a master request to read coils.

  • Request ID: Request ID of the corresponding request that is being answered.
  • Coils: Data that is to be sent to the Modbus master for the corresponding request.

This function must be called from the ModbusSlaveReadCoilsRequestCallback callback with the Request ID as provided by the argument of the callback.

func (*RS485Bricklet) ModbusMasterReadCoils(slaveAddress uint8, startingAddress uint32, count uint16) (requestID uint8, err error)
Parameters:
  • slaveAddress – Type: uint8, Range: [0 to 247]
  • startingAddress – Type: uint32, Range: [1 to 216]
  • count – Type: uint16, Range: [1 to 2000]
Returns:
  • requestID – Type: uint8, Range: [0 to 255]
  • err – Type: error

In Modbus master mode this function can be used to read coils from a slave. This function creates a Modbus function code 1 request.

  • Slave Address: Address of the target Modbus slave.
  • Starting Address: Number of the first coil to read. For backwards compatibility reasons this parameter is called Starting Address. It is not an address, but instead a coil number in the range of 1 to 65536.
  • Count: Number of coils to read.

Upon success the function will return a non-zero request ID which will represent the current request initiated by the Modbus master. In case of failure the returned request ID will be 0.

When successful this function will also invoke the ModbusMasterReadCoilsResponseCallback callback. In this callback the Request ID provided by the callback argument must be matched with the Request ID returned from this function to verify that the callback is indeed for a particular request.

func (*RS485Bricklet) ModbusSlaveAnswerReadHoldingRegistersRequest(requestID uint8, holdingRegisters []uint16) (err error)
Parameters:
  • requestID – Type: uint8, Range: [0 to 255]
  • holdingRegisters – Type: []uint16, Length: variable, Range: [0 to 216 - 1]
Returns:
  • err – Type: error

In Modbus slave mode this function can be used to answer a master request to read holding registers.

  • Request ID: Request ID of the corresponding request that is being answered.
  • Holding Registers: Data that is to be sent to the Modbus master for the corresponding request.

This function must be called from the ModbusSlaveReadHoldingRegistersRequestCallback callback with the Request ID as provided by the argument of the callback.

func (*RS485Bricklet) ModbusMasterReadHoldingRegisters(slaveAddress uint8, startingAddress uint32, count uint16) (requestID uint8, err error)
Parameters:
  • slaveAddress – Type: uint8, Range: [0 to 247]
  • startingAddress – Type: uint32, Range: [1 to 216]
  • count – Type: uint16, Range: [1 to 125]
Returns:
  • requestID – Type: uint8, Range: [0 to 255]
  • err – Type: error

In Modbus master mode this function can be used to read holding registers from a slave. This function creates a Modbus function code 3 request.

  • Slave Address: Address of the target Modbus slave.
  • Starting Address: Number of the first holding register to read. For backwards compatibility reasons this parameter is called Starting Address. It is not an address, but instead a holding register number in the range of 1 to 65536. The prefix digit 4 (for holding register) is implicit and must be omitted.
  • Count: Number of holding registers to read.

Upon success the function will return a non-zero request ID which will represent the current request initiated by the Modbus master. In case of failure the returned request ID will be 0.

When successful this function will also invoke the ModbusMasterReadHoldingRegistersResponseCallback callback. In this callback the Request ID provided by the callback argument must be matched with the Request ID returned from this function to verify that the callback is indeed for a particular request.

func (*RS485Bricklet) ModbusSlaveAnswerWriteSingleCoilRequest(requestID uint8) (err error)
Parameters:
  • requestID – Type: uint8, Range: [0 to 255]
Returns:
  • err – Type: error

In Modbus slave mode this function can be used to answer a master request to write a single coil.

  • Request ID: Request ID of the corresponding request that is being answered.

This function must be called from the ModbusSlaveWriteSingleCoilRequestCallback callback with the Request ID as provided by the arguments of the callback.

func (*RS485Bricklet) ModbusMasterWriteSingleCoil(slaveAddress uint8, coilAddress uint32, coilValue bool) (requestID uint8, err error)
Parameters:
  • slaveAddress – Type: uint8, Range: [0 to 247]
  • coilAddress – Type: uint32, Range: [1 to 216]
  • coilValue – Type: bool
Returns:
  • requestID – Type: uint8, Range: [0 to 255]
  • err – Type: error

In Modbus master mode this function can be used to write a single coil of a slave. This function creates a Modbus function code 5 request.

  • Slave Address: Address of the target Modbus slave.
  • Coil Address: Number of the coil to be written. For backwards compatibility reasons, this parameter is called Starting Address. It is not an address, but instead a coil number in the range of 1 to 65536.
  • Coil Value: Value to be written.

Upon success the function will return a non-zero request ID which will represent the current request initiated by the Modbus master. In case of failure the returned request ID will be 0.

When successful this function will also invoke the ModbusMasterWriteSingleCoilResponseCallback callback. In this callback the Request ID provided by the callback argument must be matched with the Request ID returned from this function to verify that the callback is indeed for a particular request.

func (*RS485Bricklet) ModbusSlaveAnswerWriteSingleRegisterRequest(requestID uint8) (err error)
Parameters:
  • requestID – Type: uint8, Range: [0 to 255]
Returns:
  • err – Type: error

In Modbus slave mode this function can be used to answer a master request to write a single register.

  • Request ID: Request ID of the corresponding request that is being answered.

This function must be called from the ModbusSlaveWriteSingleRegisterRequestCallback callback with the Request ID, Register Address and Register Value as provided by the arguments of the callback.

func (*RS485Bricklet) ModbusMasterWriteSingleRegister(slaveAddress uint8, registerAddress uint32, registerValue uint16) (requestID uint8, err error)
Parameters:
  • slaveAddress – Type: uint8, Range: [0 to 247]
  • registerAddress – Type: uint32, Range: [1 to 216]
  • registerValue – Type: uint16, Range: [0 to 216 - 1]
Returns:
  • requestID – Type: uint8, Range: [0 to 255]
  • err – Type: error

In Modbus master mode this function can be used to write a single holding register of a slave. This function creates a Modbus function code 6 request.

  • Slave Address: Address of the target Modbus slave.
  • Register Address: Number of the holding register to be written. For backwards compatibility reasons, this parameter is called Starting Address. It is not an address, but instead a holding register number in the range of 1 to 65536. The prefix digit 4 (for holding register) is implicit and must be omitted.
  • Register Value: Value to be written.

Upon success the function will return a non-zero request ID which will represent the current request initiated by the Modbus master. In case of failure the returned request ID will be 0.

When successful this function will also invoke the ModbusMasterWriteSingleRegisterResponseCallback callback. In this callback the Request ID provided by the callback argument must be matched with the Request ID returned from this function to verify that the callback is indeed for a particular request.

func (*RS485Bricklet) ModbusSlaveAnswerWriteMultipleCoilsRequest(requestID uint8) (err error)
Parameters:
  • requestID – Type: uint8, Range: [0 to 255]
Returns:
  • err – Type: error

In Modbus slave mode this function can be used to answer a master request to write multiple coils.

  • Request ID: Request ID of the corresponding request that is being answered.

This function must be called from the ModbusSlaveWriteMultipleCoilsRequestCallback callback with the Request ID of the callback.

func (*RS485Bricklet) ModbusMasterWriteMultipleCoils(slaveAddress uint8, startingAddress uint32, coils []bool) (requestID uint8, err error)
Parameters:
  • slaveAddress – Type: uint8, Range: [0 to 247]
  • startingAddress – Type: uint32, Range: [1 to 216]
  • coils – Type: []bool, Length: variable
Returns:
  • requestID – Type: uint8, Range: [0 to 255]
  • err – Type: error

In Modbus master mode this function can be used to write multiple coils of a slave. This function creates a Modbus function code 15 request.

  • Slave Address: Address of the target Modbus slave.
  • Starting Address: Number of the first coil to write. For backwards compatibility reasons, this parameter is called Starting Address.It is not an address, but instead a coil number in the range of 1 to 65536.

Upon success the function will return a non-zero request ID which will represent the current request initiated by the Modbus master. In case of failure the returned request ID will be 0.

When successful this function will also invoke the ModbusMasterWriteMultipleCoilsResponseCallback callback. In this callback the Request ID provided by the callback argument must be matched with the Request ID returned from this function to verify that the callback is indeed for a particular request.

func (*RS485Bricklet) ModbusSlaveAnswerWriteMultipleRegistersRequest(requestID uint8) (err error)
Parameters:
  • requestID – Type: uint8, Range: [0 to 255]
Returns:
  • err – Type: error

In Modbus slave mode this function can be used to answer a master request to write multiple registers.

  • Request ID: Request ID of the corresponding request that is being answered.

This function must be called from the ModbusSlaveWriteMultipleRegistersRequestCallback callback with the Request ID of the callback.

func (*RS485Bricklet) ModbusMasterWriteMultipleRegisters(slaveAddress uint8, startingAddress uint32, registers []uint16) (requestID uint8, err error)
Parameters:
  • slaveAddress – Type: uint8, Range: [0 to 247]
  • startingAddress – Type: uint32, Range: [1 to 216]
  • registers – Type: []uint16, Length: variable, Range: [0 to 216 - 1]
Returns:
  • requestID – Type: uint8, Range: [0 to 255]
  • err – Type: error

In Modbus master mode this function can be used to write multiple registers of a slave. This function creates a Modbus function code 16 request.

  • Slave Address: Address of the target Modbus slave.
  • Starting Address: Number of the first holding register to write. For backwards compatibility reasons, this parameter is called Starting Address. It is not an address, but instead a holding register number in the range of 1 to 65536. The prefix digit 4 (for holding register) is implicit and must be omitted.

Upon success the function will return a non-zero request ID which will represent the current request initiated by the Modbus master. In case of failure the returned request ID will be 0.

When successful this function will also invoke the ModbusMasterWriteMultipleRegistersResponseCallback callback. In this callback the Request ID provided by the callback argument must be matched with the Request ID returned from this function to verify that the callback is indeed for a particular request.

func (*RS485Bricklet) ModbusSlaveAnswerReadDiscreteInputsRequest(requestID uint8, discreteInputs []bool) (err error)
Parameters:
  • requestID – Type: uint8, Range: [0 to 255]
  • discreteInputs – Type: []bool, Length: variable
Returns:
  • err – Type: error

In Modbus slave mode this function can be used to answer a master request to read discrete inputs.

  • Request ID: Request ID of the corresponding request that is being answered.
  • Discrete Inputs: Data that is to be sent to the Modbus master for the corresponding request.

This function must be called from the ModbusSlaveReadDiscreteInputsRequestCallback callback with the Request ID as provided by the argument of the callback.

func (*RS485Bricklet) ModbusMasterReadDiscreteInputs(slaveAddress uint8, startingAddress uint32, count uint16) (requestID uint8, err error)
Parameters:
  • slaveAddress – Type: uint8, Range: [0 to 247]
  • startingAddress – Type: uint32, Range: [1 to 216]
  • count – Type: uint16, Range: [1 to 2000]
Returns:
  • requestID – Type: uint8, Range: [0 to 255]
  • err – Type: error

In Modbus master mode this function can be used to read discrete inputs from a slave. This function creates a Modbus function code 2 request.

  • Slave Address: Address of the target Modbus slave.
  • Starting Address: Number of the first discrete input to read. For backwards compatibility reasons, this parameter is called Starting Address. It is not an address, but instead a discrete input number in the range of 1 to 65536. The prefix digit 1 (for discrete input) is implicit and must be omitted.
  • Count: Number of discrete inputs to read.

Upon success the function will return a non-zero request ID which will represent the current request initiated by the Modbus master. In case of failure the returned request ID will be 0.

When successful this function will also invoke the ModbusMasterReadDiscreteInputsResponseCallback callback. In this callback the Request ID provided by the callback argument must be matched with the Request ID returned from this function to verify that the callback is indeed for a particular request.

func (*RS485Bricklet) ModbusSlaveAnswerReadInputRegistersRequest(requestID uint8, inputRegisters []uint16) (err error)
Parameters:
  • requestID – Type: uint8, Range: [0 to 255]
  • inputRegisters – Type: []uint16, Length: variable, Range: [0 to 216 - 1]
Returns:
  • err – Type: error

In Modbus slave mode this function can be used to answer a master request to read input registers.

  • Request ID: Request ID of the corresponding request that is being answered.
  • Input Registers: Data that is to be sent to the Modbus master for the corresponding request.

This function must be called from the ModbusSlaveReadInputRegistersRequestCallback callback with the Request ID as provided by the argument of the callback.

func (*RS485Bricklet) ModbusMasterReadInputRegisters(slaveAddress uint8, startingAddress uint32, count uint16) (requestID uint8, err error)
Parameters:
  • slaveAddress – Type: uint8, Range: [0 to 247]
  • startingAddress – Type: uint32, Range: [1 to 216]
  • count – Type: uint16, Range: [1 to 125]
Returns:
  • requestID – Type: uint8, Range: [0 to 255]
  • err – Type: error

In Modbus master mode this function can be used to read input registers from a slave. This function creates a Modbus function code 4 request.

  • Slave Address: Address of the target Modbus slave.
  • Starting Address: Number of the first input register to read. For backwards compatibility reasons, this parameter is called Starting Address. It is not an address, but instead an input register number in the range of 1 to 65536. The prefix digit 3 (for input register) is implicit and must be omitted.
  • Count: Number of input registers to read.

Upon success the function will return a non-zero request ID which will represent the current request initiated by the Modbus master. In case of failure the returned request ID will be 0.

When successful this function will also invoke the ModbusMasterReadInputRegistersResponseCallback callback. In this callback the Request ID provided by the callback argument must be matched with the Request ID returned from this function to verify that the callback is indeed for a particular request.

func (*RS485Bricklet) GetSPITFPErrorCount() (errorCountAckChecksum uint32, errorCountMessageChecksum uint32, errorCountFrame uint32, errorCountOverflow uint32, err error)
Returns:
  • errorCountAckChecksum – Type: uint32, Range: [0 to 232 - 1]
  • errorCountMessageChecksum – Type: uint32, Range: [0 to 232 - 1]
  • errorCountFrame – Type: uint32, Range: [0 to 232 - 1]
  • errorCountOverflow – Type: uint32, Range: [0 to 232 - 1]
  • err – Type: error

Returns the error count for the communication between Brick and Bricklet.

The errors are divided into

  • ACK checksum errors,
  • message checksum errors,
  • framing errors and
  • overflow errors.

The errors counts are for errors that occur on the Bricklet side. All Bricks have a similar function that returns the errors on the Brick side.

func (*RS485Bricklet) SetStatusLEDConfig(config uint8) (err error)
Parameters:
  • config – Type: uint8, Range: See constants, Default: 3
Returns:
  • err – Type: error

Sets the status LED configuration. By default the LED shows communication traffic between Brick and Bricklet, it flickers once for every 10 received data packets.

You can also turn the LED permanently on/off or show a heartbeat.

If the Bricklet is in bootloader mode, the LED is will show heartbeat by default.

The following constants are available for this function:

For config:

  • rs485_bricklet.StatusLEDConfigOff = 0
  • rs485_bricklet.StatusLEDConfigOn = 1
  • rs485_bricklet.StatusLEDConfigShowHeartbeat = 2
  • rs485_bricklet.StatusLEDConfigShowStatus = 3
func (*RS485Bricklet) GetStatusLEDConfig() (config uint8, err error)
Returns:
  • config – Type: uint8, Range: See constants, Default: 3
  • err – Type: error

Returns the configuration as set by SetStatusLEDConfig()

The following constants are available for this function:

For config:

  • rs485_bricklet.StatusLEDConfigOff = 0
  • rs485_bricklet.StatusLEDConfigOn = 1
  • rs485_bricklet.StatusLEDConfigShowHeartbeat = 2
  • rs485_bricklet.StatusLEDConfigShowStatus = 3
func (*RS485Bricklet) GetChipTemperature() (temperature int16, err error)
Returns:
  • temperature – Type: int16, Unit: 1 °C, Range: [-215 to 215 - 1]
  • err – Type: error

Returns the temperature as measured inside the microcontroller. The value returned is not the ambient temperature!

The temperature is only proportional to the real temperature and it has bad accuracy. Practically it is only useful as an indicator for temperature changes.

func (*RS485Bricklet) Reset() (err error)
Returns:
  • err – Type: error

Calling this function will reset the Bricklet. All configurations will be lost.

After a reset you have to create new device objects, calling functions on the existing ones will result in undefined behavior!

func (*RS485Bricklet) GetIdentity() (uid string, connectedUid string, position rune, hardwareVersion [3]uint8, firmwareVersion [3]uint8, deviceIdentifier uint16, err error)
Returns:
  • uid – Type: string, Length: up to 8
  • connectedUid – Type: string, Length: up to 8
  • position – Type: rune, Range: ['a' to 'h', 'z']
  • hardwareVersion – Type: [3]uint8
    • 0: major – Type: uint8, Range: [0 to 255]
    • 1: minor – Type: uint8, Range: [0 to 255]
    • 2: revision – Type: uint8, Range: [0 to 255]
  • firmwareVersion – Type: [3]uint8
    • 0: major – Type: uint8, Range: [0 to 255]
    • 1: minor – Type: uint8, Range: [0 to 255]
    • 2: revision – Type: uint8, Range: [0 to 255]
  • deviceIdentifier – Type: uint16, Range: [0 to 216 - 1]
  • err – Type: error

Returns the UID, the UID where the Bricklet is connected to, the position, the hardware and firmware version as well as the device identifier.

The position can be 'a', 'b', 'c', 'd', 'e', 'f', 'g' or 'h' (Bricklet Port). A Bricklet connected to an Isolator Bricklet is always at position 'z'.

The device identifier numbers can be found here. There is also a constant for the device identifier of this Bricklet.

Callback Configuration Functions

func (*RS485Bricklet) EnableReadCallback() (err error)
Returns:
  • err – Type: error

Enables the ReadCallback callback. This will disable the FrameReadableCallback callback.

By default the callback is disabled.

func (*RS485Bricklet) DisableReadCallback() (err error)
Returns:
  • err – Type: error

Disables the ReadCallback callback.

By default the callback is disabled.

func (*RS485Bricklet) IsReadCallbackEnabled() (enabled bool, err error)
Returns:
  • enabled – Type: bool, Default: false
  • err – Type: error

Returns true if the ReadCallback callback is enabled, false otherwise.

func (*RS485Bricklet) EnableErrorCountCallback() (err error)
Returns:
  • err – Type: error

Enables the ErrorCountCallback callback.

By default the callback is disabled.

func (*RS485Bricklet) DisableErrorCountCallback() (err error)
Returns:
  • err – Type: error

Disables the ErrorCountCallback callback.

By default the callback is disabled.

func (*RS485Bricklet) IsErrorCountCallbackEnabled() (enabled bool, err error)
Returns:
  • enabled – Type: bool, Default: true
  • err – Type: error

Returns true if the ErrorCountCallback callback is enabled, false otherwise.

func (*RS485Bricklet) SetFrameReadableCallbackConfiguration(frameSize uint16) (err error)
Parameters:
  • frameSize – Type: uint16, Unit: 1 B, Range: [0 to 9216], Default: 0
Returns:
  • err – Type: error

Configures the FrameReadableCallback callback. The frame size is the number of bytes, that have to be readable to trigger the callback. A frame size of 0 disables the callback. A frame size greater than 0 enables the callback and disables the ReadCallback callback.

By default the callback is disabled.

New in version 2.0.5 (Plugin).

func (*RS485Bricklet) GetFrameReadableCallbackConfiguration() (frameSize uint16, err error)
Returns:
  • frameSize – Type: uint16, Unit: 1 B, Range: [0 to 9216], Default: 0
  • err – Type: error

Returns the callback configuration as set by SetFrameReadableCallbackConfiguration().

New in version 2.0.5 (Plugin).

Callbacks

Callbacks can be registered to receive time critical or recurring data from the device. The registration is done with the corresponding Register*Callback function, which returns a unique callback ID. This ID can be used to deregister the callback later with the corresponding Deregister*Callback function.

Note

Using callbacks for recurring events is always preferred compared to using getters. It will use less USB bandwidth and the latency will be a lot better, since there is no round trip time.

func (*RS485Bricklet) RegisterReadCallback(func(message []rune)) (registrationId uint64)
Callback Parameters:
  • message – Type: []rune, Length: variable
Returns:
  • registrationId – Type: uint64

This callback is called if new data is available.

To enable this callback, use EnableReadCallback().

Note

If reconstructing the value fails, the callback is triggered with nil for message.

func (*RS485Bricklet) RegisterErrorCountCallback(func(overrunErrorCount uint32, parityErrorCount uint32)) (registrationId uint64)
Callback Parameters:
  • overrunErrorCount – Type: uint32, Range: [0 to 232 - 1]
  • parityErrorCount – Type: uint32, Range: [0 to 232 - 1]
Returns:
  • registrationId – Type: uint64

This callback is called if a new error occurs. It returns the current overrun and parity error count.

func (*RS485Bricklet) RegisterModbusSlaveReadCoilsRequestCallback(func(requestID uint8, startingAddress uint32, count uint16)) (registrationId uint64)
Callback Parameters:
  • requestID – Type: uint8, Range: [0 to 255]
  • startingAddress – Type: uint32, Range: [1 to 216]
  • count – Type: uint16, Range: [1 to 2000]
Returns:
  • registrationId – Type: uint64

This callback is called only in Modbus slave mode when the slave receives a valid request from a Modbus master to read coils. The callback parameters are request ID of the request, the number of the first coil to be read and the number of coils to be read as received by the request. The number of the first coil is called starting address for backwards compatibility reasons. It is not an address, but instead a coil number in the range of 1 to 65536.

To send a response of this request use ModbusSlaveAnswerReadCoilsRequest().

func (*RS485Bricklet) RegisterModbusMasterReadCoilsResponseCallback(func(coils []bool, requestID uint8, exceptionCode int8)) (registrationId uint64)
Callback Parameters:
  • requestID – Type: uint8, Range: [0 to 255]
  • exceptionCode – Type: int8, Range: See constants
  • coils – Type: []bool, Length: variable
Returns:
  • registrationId – Type: uint64

This callback is called only in Modbus master mode when the master receives a valid response of a request to read coils.

The callback parameters are request ID of the request, exception code of the response and the data as received by the response.

Any non-zero exception code indicates a problem. If the exception code is greater than 0 then the number represents a Modbus exception code. If it is less than 0 then it represents other errors. For example, -1 indicates that the request timed out or that the master did not receive any valid response of the request within the master request timeout period as set by SetModbusConfiguration().

Note

If reconstructing the value fails, the callback is triggered with nil for coils.

The following constants are available for this function:

For exceptionCode:

  • rs485_bricklet.ExceptionCodeTimeout = -1
  • rs485_bricklet.ExceptionCodeSuccess = 0
  • rs485_bricklet.ExceptionCodeIllegalFunction = 1
  • rs485_bricklet.ExceptionCodeIllegalDataAddress = 2
  • rs485_bricklet.ExceptionCodeIllegalDataValue = 3
  • rs485_bricklet.ExceptionCodeSlaveDeviceFailure = 4
  • rs485_bricklet.ExceptionCodeAcknowledge = 5
  • rs485_bricklet.ExceptionCodeSlaveDeviceBusy = 6
  • rs485_bricklet.ExceptionCodeMemoryParityError = 8
  • rs485_bricklet.ExceptionCodeGatewayPathUnavailable = 10
  • rs485_bricklet.ExceptionCodeGatewayTargetDeviceFailedToRespond = 11
func (*RS485Bricklet) RegisterModbusSlaveReadHoldingRegistersRequestCallback(func(requestID uint8, startingAddress uint32, count uint16)) (registrationId uint64)
Callback Parameters:
  • requestID – Type: uint8, Range: [0 to 255]
  • startingAddress – Type: uint32, Range: [1 to 216]
  • count – Type: uint16, Range: [1 to 125]
Returns:
  • registrationId – Type: uint64

This callback is called only in Modbus slave mode when the slave receives a valid request from a Modbus master to read holding registers. The callback parameters are request ID of the request, the number of the first holding register to be read and the number of holding registers to be read as received by the request. The number of the first holding register is called starting address for backwards compatibility reasons. It is not an address, but instead a holding register number in the range of 1 to 65536. The prefix digit 4 (for holding register) is omitted.

To send a response of this request use ModbusSlaveAnswerReadHoldingRegistersRequest().

func (*RS485Bricklet) RegisterModbusMasterReadHoldingRegistersResponseCallback(func(holdingRegisters []uint16, requestID uint8, exceptionCode int8)) (registrationId uint64)
Callback Parameters:
  • requestID – Type: uint8, Range: [0 to 255]
  • exceptionCode – Type: int8, Range: See constants
  • holdingRegisters – Type: []uint16, Length: variable, Range: [0 to 216 - 1]
Returns:
  • registrationId – Type: uint64

This callback is called only in Modbus master mode when the master receives a valid response of a request to read holding registers.

The callback parameters are request ID of the request, exception code of the response and the data as received by the response.

Any non-zero exception code indicates a problem. If the exception code is greater than 0 then the number represents a Modbus exception code. If it is less than 0 then it represents other errors. For example, -1 indicates that the request timed out or that the master did not receive any valid response of the request within the master request timeout period as set by SetModbusConfiguration().

Note

If reconstructing the value fails, the callback is triggered with nil for holdingRegisters.

The following constants are available for this function:

For exceptionCode:

  • rs485_bricklet.ExceptionCodeTimeout = -1
  • rs485_bricklet.ExceptionCodeSuccess = 0
  • rs485_bricklet.ExceptionCodeIllegalFunction = 1
  • rs485_bricklet.ExceptionCodeIllegalDataAddress = 2
  • rs485_bricklet.ExceptionCodeIllegalDataValue = 3
  • rs485_bricklet.ExceptionCodeSlaveDeviceFailure = 4
  • rs485_bricklet.ExceptionCodeAcknowledge = 5
  • rs485_bricklet.ExceptionCodeSlaveDeviceBusy = 6
  • rs485_bricklet.ExceptionCodeMemoryParityError = 8
  • rs485_bricklet.ExceptionCodeGatewayPathUnavailable = 10
  • rs485_bricklet.ExceptionCodeGatewayTargetDeviceFailedToRespond = 11
func (*RS485Bricklet) RegisterModbusSlaveWriteSingleCoilRequestCallback(func(requestID uint8, coilAddress uint32, coilValue bool)) (registrationId uint64)
Callback Parameters:
  • requestID – Type: uint8, Range: [0 to 255]
  • coilAddress – Type: uint32, Range: [1 to 216]
  • coilValue – Type: bool
Returns:
  • registrationId – Type: uint64

This callback is called only in Modbus slave mode when the slave receives a valid request from a Modbus master to write a single coil. The callback parameters are request ID of the request, the number of the coil and the value of coil to be written as received by the request. The number of the coil is called coil address for backwards compatibility reasons. It is not an address, but instead a coil number in the range of 1 to 65536.

To send a response of this request use ModbusSlaveAnswerWriteSingleCoilRequest().

func (*RS485Bricklet) RegisterModbusMasterWriteSingleCoilResponseCallback(func(requestID uint8, exceptionCode int8)) (registrationId uint64)
Callback Parameters:
  • requestID – Type: uint8, Range: [0 to 255]
  • exceptionCode – Type: int8, Range: See constants
Returns:
  • registrationId – Type: uint64

This callback is called only in Modbus master mode when the master receives a valid response of a request to write a single coil.

The callback parameters are request ID of the request and exception code of the response.

Any non-zero exception code indicates a problem. If the exception code is greater than 0 then the number represents a Modbus exception code. If it is less than 0 then it represents other errors. For example, -1 indicates that the request timed out or that the master did not receive any valid response of the request within the master request timeout period as set by SetModbusConfiguration().

The following constants are available for this function:

For exceptionCode:

  • rs485_bricklet.ExceptionCodeTimeout = -1
  • rs485_bricklet.ExceptionCodeSuccess = 0
  • rs485_bricklet.ExceptionCodeIllegalFunction = 1
  • rs485_bricklet.ExceptionCodeIllegalDataAddress = 2
  • rs485_bricklet.ExceptionCodeIllegalDataValue = 3
  • rs485_bricklet.ExceptionCodeSlaveDeviceFailure = 4
  • rs485_bricklet.ExceptionCodeAcknowledge = 5
  • rs485_bricklet.ExceptionCodeSlaveDeviceBusy = 6
  • rs485_bricklet.ExceptionCodeMemoryParityError = 8
  • rs485_bricklet.ExceptionCodeGatewayPathUnavailable = 10
  • rs485_bricklet.ExceptionCodeGatewayTargetDeviceFailedToRespond = 11
func (*RS485Bricklet) RegisterModbusSlaveWriteSingleRegisterRequestCallback(func(requestID uint8, registerAddress uint32, registerValue uint16)) (registrationId uint64)
Callback Parameters:
  • requestID – Type: uint8, Range: [0 to 255]
  • registerAddress – Type: uint32, Range: [1 to 216]
  • registerValue – Type: uint16, Range: [0 to 216 - 1]
Returns:
  • registrationId – Type: uint64

This callback is called only in Modbus slave mode when the slave receives a valid request from a Modbus master to write a single holding register. The callback parameters are request ID of the request, the number of the holding register and the register value to be written as received by the request. The number of the holding register is called starting address for backwards compatibility reasons. It is not an address, but instead a holding register number in the range of 1 to 65536. The prefix digit 4 (for holding register) is omitted.

To send a response of this request use ModbusSlaveAnswerWriteSingleRegisterRequest().

func (*RS485Bricklet) RegisterModbusMasterWriteSingleRegisterResponseCallback(func(requestID uint8, exceptionCode int8)) (registrationId uint64)
Callback Parameters:
  • requestID – Type: uint8, Range: [0 to 255]
  • exceptionCode – Type: int8, Range: See constants
Returns:
  • registrationId – Type: uint64

This callback is called only in Modbus master mode when the master receives a valid response of a request to write a single register.

The callback parameters are request ID of the request and exception code of the response.

Any non-zero exception code indicates a problem. If the exception code is greater than 0 then the number represents a Modbus exception code. If it is less than 0 then it represents other errors. For example, -1 indicates that the request timed out or that the master did not receive any valid response of the request within the master request timeout period as set by SetModbusConfiguration().

The following constants are available for this function:

For exceptionCode:

  • rs485_bricklet.ExceptionCodeTimeout = -1
  • rs485_bricklet.ExceptionCodeSuccess = 0
  • rs485_bricklet.ExceptionCodeIllegalFunction = 1
  • rs485_bricklet.ExceptionCodeIllegalDataAddress = 2
  • rs485_bricklet.ExceptionCodeIllegalDataValue = 3
  • rs485_bricklet.ExceptionCodeSlaveDeviceFailure = 4
  • rs485_bricklet.ExceptionCodeAcknowledge = 5
  • rs485_bricklet.ExceptionCodeSlaveDeviceBusy = 6
  • rs485_bricklet.ExceptionCodeMemoryParityError = 8
  • rs485_bricklet.ExceptionCodeGatewayPathUnavailable = 10
  • rs485_bricklet.ExceptionCodeGatewayTargetDeviceFailedToRespond = 11
func (*RS485Bricklet) RegisterModbusSlaveWriteMultipleCoilsRequestCallback(func(coils []bool, requestID uint8, startingAddress uint32)) (registrationId uint64)
Callback Parameters:
  • requestID – Type: uint8, Range: [0 to 255]
  • startingAddress – Type: uint32, Range: [1 to 216]
  • coils – Type: []bool, Length: variable
Returns:
  • registrationId – Type: uint64

This callback is called only in Modbus slave mode when the slave receives a valid request from a Modbus master to write multiple coils. The callback parameters are request ID of the request, the number of the first coil and the data to be written as received by the request. The number of the first coil is called starting address for backwards compatibility reasons. It is not an address, but instead a coil number in the range of 1 to 65536.

To send a response of this request use ModbusSlaveAnswerWriteMultipleCoilsRequest().

Note

If reconstructing the value fails, the callback is triggered with nil for coils.

func (*RS485Bricklet) RegisterModbusMasterWriteMultipleCoilsResponseCallback(func(requestID uint8, exceptionCode int8)) (registrationId uint64)
Callback Parameters:
  • requestID – Type: uint8, Range: [0 to 255]
  • exceptionCode – Type: int8, Range: See constants
Returns:
  • registrationId – Type: uint64

This callback is called only in Modbus master mode when the master receives a valid response of a request to read coils.

The callback parameters are request ID of the request and exception code of the response.

Any non-zero exception code indicates a problem. If the exception code is greater than 0 then the number represents a Modbus exception code. If it is less than 0 then it represents other errors. For example, -1 indicates that the request timedout or that the master did not receive any valid response of the request within the master request timeout period as set by SetModbusConfiguration().

The following constants are available for this function:

For exceptionCode:

  • rs485_bricklet.ExceptionCodeTimeout = -1
  • rs485_bricklet.ExceptionCodeSuccess = 0
  • rs485_bricklet.ExceptionCodeIllegalFunction = 1
  • rs485_bricklet.ExceptionCodeIllegalDataAddress = 2
  • rs485_bricklet.ExceptionCodeIllegalDataValue = 3
  • rs485_bricklet.ExceptionCodeSlaveDeviceFailure = 4
  • rs485_bricklet.ExceptionCodeAcknowledge = 5
  • rs485_bricklet.ExceptionCodeSlaveDeviceBusy = 6
  • rs485_bricklet.ExceptionCodeMemoryParityError = 8
  • rs485_bricklet.ExceptionCodeGatewayPathUnavailable = 10
  • rs485_bricklet.ExceptionCodeGatewayTargetDeviceFailedToRespond = 11
func (*RS485Bricklet) RegisterModbusSlaveWriteMultipleRegistersRequestCallback(func(registers []uint16, requestID uint8, startingAddress uint32)) (registrationId uint64)
Callback Parameters:
  • requestID – Type: uint8, Range: [0 to 255]
  • startingAddress – Type: uint32, Range: [1 to 216]
  • registers – Type: []uint16, Length: variable, Range: [0 to 216 - 1]
Returns:
  • registrationId – Type: uint64

This callback is called only in Modbus slave mode when the slave receives a valid request from a Modbus master to write multiple holding registers. The callback parameters are request ID of the request, the number of the first holding register and the data to be written as received by the request. The number of the first holding register is called starting address for backwards compatibility reasons. It is not an address, but instead a holding register number in the range of 1 to 65536. The prefix digit 4 (for holding register) is omitted.

To send a response of this request use ModbusSlaveAnswerWriteMultipleRegistersRequest().

Note

If reconstructing the value fails, the callback is triggered with nil for registers.

func (*RS485Bricklet) RegisterModbusMasterWriteMultipleRegistersResponseCallback(func(requestID uint8, exceptionCode int8)) (registrationId uint64)
Callback Parameters:
  • requestID – Type: uint8, Range: [0 to 255]
  • exceptionCode – Type: int8, Range: See constants
Returns:
  • registrationId – Type: uint64

This callback is called only in Modbus master mode when the master receives a valid response of a request to write multiple registers.

The callback parameters are request ID of the request and exception code of the response.

Any non-zero exception code indicates a problem. If the exception code is greater than 0 then the number represents a Modbus exception code. If it is less than 0 then it represents other errors. For example, -1 indicates that the request timedout or that the master did not receive any valid response of the request within the master request timeout period as set by SetModbusConfiguration().

The following constants are available for this function:

For exceptionCode:

  • rs485_bricklet.ExceptionCodeTimeout = -1
  • rs485_bricklet.ExceptionCodeSuccess = 0
  • rs485_bricklet.ExceptionCodeIllegalFunction = 1
  • rs485_bricklet.ExceptionCodeIllegalDataAddress = 2
  • rs485_bricklet.ExceptionCodeIllegalDataValue = 3
  • rs485_bricklet.ExceptionCodeSlaveDeviceFailure = 4
  • rs485_bricklet.ExceptionCodeAcknowledge = 5
  • rs485_bricklet.ExceptionCodeSlaveDeviceBusy = 6
  • rs485_bricklet.ExceptionCodeMemoryParityError = 8
  • rs485_bricklet.ExceptionCodeGatewayPathUnavailable = 10
  • rs485_bricklet.ExceptionCodeGatewayTargetDeviceFailedToRespond = 11
func (*RS485Bricklet) RegisterModbusSlaveReadDiscreteInputsRequestCallback(func(requestID uint8, startingAddress uint32, count uint16)) (registrationId uint64)
Callback Parameters:
  • requestID – Type: uint8, Range: [0 to 255]
  • startingAddress – Type: uint32, Range: [1 to 216]
  • count – Type: uint16, Range: [1 to 2000]
Returns:
  • registrationId – Type: uint64

This callback is called only in Modbus slave mode when the slave receives a valid request from a Modbus master to read discrete inputs. The callback parameters are request ID of the request, the number of the first discrete input and the number of discrete inputs to be read as received by the request. The number of the first discrete input is called starting address for backwards compatibility reasons. It is not an address, but instead a discrete input number in the range of 1 to 65536. The prefix digit 1 (for discrete input) is omitted.

To send a response of this request use ModbusSlaveAnswerReadDiscreteInputsRequest().

func (*RS485Bricklet) RegisterModbusMasterReadDiscreteInputsResponseCallback(func(discreteInputs []bool, requestID uint8, exceptionCode int8)) (registrationId uint64)
Callback Parameters:
  • requestID – Type: uint8, Range: [0 to 255]
  • exceptionCode – Type: int8, Range: See constants
  • discreteInputs – Type: []bool, Length: variable
Returns:
  • registrationId – Type: uint64

This callback is called only in Modbus master mode when the master receives a valid response of a request to read discrete inputs.

The callback parameters are request ID of the request, exception code of the response and the data as received by the response.

Any non-zero exception code indicates a problem. If the exception code is greater than 0 then the number represents a Modbus exception code. If it is less than 0 then it represents other errors. For example, -1 indicates that the request timedout or that the master did not receive any valid response of the request within the master request timeout period as set by SetModbusConfiguration().

Note

If reconstructing the value fails, the callback is triggered with nil for discreteInputs.

The following constants are available for this function:

For exceptionCode:

  • rs485_bricklet.ExceptionCodeTimeout = -1
  • rs485_bricklet.ExceptionCodeSuccess = 0
  • rs485_bricklet.ExceptionCodeIllegalFunction = 1
  • rs485_bricklet.ExceptionCodeIllegalDataAddress = 2
  • rs485_bricklet.ExceptionCodeIllegalDataValue = 3
  • rs485_bricklet.ExceptionCodeSlaveDeviceFailure = 4
  • rs485_bricklet.ExceptionCodeAcknowledge = 5
  • rs485_bricklet.ExceptionCodeSlaveDeviceBusy = 6
  • rs485_bricklet.ExceptionCodeMemoryParityError = 8
  • rs485_bricklet.ExceptionCodeGatewayPathUnavailable = 10
  • rs485_bricklet.ExceptionCodeGatewayTargetDeviceFailedToRespond = 11
func (*RS485Bricklet) RegisterModbusSlaveReadInputRegistersRequestCallback(func(requestID uint8, startingAddress uint32, count uint16)) (registrationId uint64)
Callback Parameters:
  • requestID – Type: uint8, Range: [0 to 255]
  • startingAddress – Type: uint32, Range: [1 to 216]
  • count – Type: uint16, Range: [1 to 125]
Returns:
  • registrationId – Type: uint64

This callback is called only in Modbus slave mode when the slave receives a valid request from a Modbus master to read input registers. The callback parameters are request ID of the request, the number of the first input register and the number of input registers to be read as received by the request. The number of the first input register is called starting address for backwards compatibility reasons. It is not an address, but instead a input register number in the range of 1 to 65536. The prefix digit 3 (for input register) is omitted.

To send a response of this request use ModbusSlaveAnswerReadInputRegistersRequest().

func (*RS485Bricklet) RegisterModbusMasterReadInputRegistersResponseCallback(func(inputRegisters []uint16, requestID uint8, exceptionCode int8)) (registrationId uint64)
Callback Parameters:
  • requestID – Type: uint8, Range: [0 to 255]
  • exceptionCode – Type: int8, Range: See constants
  • inputRegisters – Type: []uint16, Length: variable, Range: [0 to 216 - 1]
Returns:
  • registrationId – Type: uint64

This callback is called only in Modbus master mode when the master receives a valid response of a request to read input registers.

The callback parameters are request ID of the request, exception code of the response and the data as received by the response.

Any non-zero exception code indicates a problem. If the exception code is greater than 0 then the number represents a Modbus exception code. If it is less than 0 then it represents other errors. For example, -1 indicates that the request timedout or that the master did not receive any valid response of the request within the master request timeout period as set by SetModbusConfiguration().

Note

If reconstructing the value fails, the callback is triggered with nil for inputRegisters.

The following constants are available for this function:

For exceptionCode:

  • rs485_bricklet.ExceptionCodeTimeout = -1
  • rs485_bricklet.ExceptionCodeSuccess = 0
  • rs485_bricklet.ExceptionCodeIllegalFunction = 1
  • rs485_bricklet.ExceptionCodeIllegalDataAddress = 2
  • rs485_bricklet.ExceptionCodeIllegalDataValue = 3
  • rs485_bricklet.ExceptionCodeSlaveDeviceFailure = 4
  • rs485_bricklet.ExceptionCodeAcknowledge = 5
  • rs485_bricklet.ExceptionCodeSlaveDeviceBusy = 6
  • rs485_bricklet.ExceptionCodeMemoryParityError = 8
  • rs485_bricklet.ExceptionCodeGatewayPathUnavailable = 10
  • rs485_bricklet.ExceptionCodeGatewayTargetDeviceFailedToRespond = 11
func (*RS485Bricklet) RegisterFrameReadableCallback(func(frameCount uint16)) (registrationId uint64)
Callback Parameters:
  • frameCount – Type: uint16, Range: [0 to 216 - 1]
Returns:
  • registrationId – Type: uint64

This callback is called if at least one frame of data is readable. The frame size is configured with SetFrameReadableCallbackConfiguration(). The frame count parameter is the number of frames that can be read. This callback is triggered only once until Read() is called. This means, that if you have configured a frame size of X bytes, you can read exactly X bytes using the Read() function, every time the callback triggers without checking the frame count callback parameter.

New in version 2.0.5 (Plugin).

Virtual Functions

Virtual functions don't communicate with the device itself, but operate only on the API bindings device object. They can be called without the corresponding IP Connection object being connected.

func (*RS485Bricklet) GetAPIVersion() (apiVersion [3]uint8, err error)
Returns:
  • apiVersion – Type: [3]uint8
    • 0: major – Type: uint8, Range: [0 to 255]
    • 1: minor – Type: uint8, Range: [0 to 255]
    • 2: revision – Type: uint8, Range: [0 to 255]
  • err – Type: error

Returns the version of the API definition implemented by this API bindings. This is neither the release version of this API bindings nor does it tell you anything about the represented Brick or Bricklet.

func (*RS485Bricklet) GetResponseExpected(functionId uint8) (responseExpected bool, err error)
Parameters:
  • functionId – Type: uint8, Range: See constants
Returns:
  • responseExpected – Type: bool
  • err – Type: error

Returns the response expected flag for the function specified by the function ID parameter. It is true if the function is expected to send a response, false otherwise.

For getter functions this is enabled by default and cannot be disabled, because those functions will always send a response. For callback configuration functions it is enabled by default too, but can be disabled by SetResponseExpected(). For setter functions it is disabled by default and can be enabled.

Enabling the response expected flag for a setter function allows to detect timeouts and other error conditions calls of this setter as well. The device will then send a response for this purpose. If this flag is disabled for a setter function then no response is sent and errors are silently ignored, because they cannot be detected.

The following constants are available for this function:

For functionId:

  • rs485_bricklet.FunctionEnableReadCallback = 3
  • rs485_bricklet.FunctionDisableReadCallback = 4
  • rs485_bricklet.FunctionSetRS485Configuration = 6
  • rs485_bricklet.FunctionSetModbusConfiguration = 8
  • rs485_bricklet.FunctionSetMode = 10
  • rs485_bricklet.FunctionSetCommunicationLEDConfig = 12
  • rs485_bricklet.FunctionSetErrorLEDConfig = 14
  • rs485_bricklet.FunctionSetBufferConfig = 16
  • rs485_bricklet.FunctionEnableErrorCountCallback = 19
  • rs485_bricklet.FunctionDisableErrorCountCallback = 20
  • rs485_bricklet.FunctionModbusSlaveReportException = 24
  • rs485_bricklet.FunctionModbusSlaveAnswerReadCoilsRequest = 25
  • rs485_bricklet.FunctionModbusSlaveAnswerReadHoldingRegistersRequest = 27
  • rs485_bricklet.FunctionModbusSlaveAnswerWriteSingleCoilRequest = 29
  • rs485_bricklet.FunctionModbusSlaveAnswerWriteSingleRegisterRequest = 31
  • rs485_bricklet.FunctionModbusSlaveAnswerWriteMultipleCoilsRequest = 33
  • rs485_bricklet.FunctionModbusSlaveAnswerWriteMultipleRegistersRequest = 35
  • rs485_bricklet.FunctionModbusSlaveAnswerReadDiscreteInputsRequest = 37
  • rs485_bricklet.FunctionModbusSlaveAnswerReadInputRegistersRequest = 39
  • rs485_bricklet.FunctionSetFrameReadableCallbackConfiguration = 59
  • rs485_bricklet.FunctionSetWriteFirmwarePointer = 237
  • rs485_bricklet.FunctionSetStatusLEDConfig = 239
  • rs485_bricklet.FunctionReset = 243
  • rs485_bricklet.FunctionWriteUID = 248
func (*RS485Bricklet) SetResponseExpected(functionId uint8, responseExpected bool) (err error)
Parameters:
  • functionId – Type: uint8, Range: See constants
  • responseExpected – Type: bool
Returns:
  • err – Type: error

Changes the response expected flag of the function specified by the function ID parameter. This flag can only be changed for setter (default value: false) and callback configuration functions (default value: true). For getter functions it is always enabled.

Enabling the response expected flag for a setter function allows to detect timeouts and other error conditions calls of this setter as well. The device will then send a response for this purpose. If this flag is disabled for a setter function then no response is sent and errors are silently ignored, because they cannot be detected.

The following constants are available for this function:

For functionId:

  • rs485_bricklet.FunctionEnableReadCallback = 3
  • rs485_bricklet.FunctionDisableReadCallback = 4
  • rs485_bricklet.FunctionSetRS485Configuration = 6
  • rs485_bricklet.FunctionSetModbusConfiguration = 8
  • rs485_bricklet.FunctionSetMode = 10
  • rs485_bricklet.FunctionSetCommunicationLEDConfig = 12
  • rs485_bricklet.FunctionSetErrorLEDConfig = 14
  • rs485_bricklet.FunctionSetBufferConfig = 16
  • rs485_bricklet.FunctionEnableErrorCountCallback = 19
  • rs485_bricklet.FunctionDisableErrorCountCallback = 20
  • rs485_bricklet.FunctionModbusSlaveReportException = 24
  • rs485_bricklet.FunctionModbusSlaveAnswerReadCoilsRequest = 25
  • rs485_bricklet.FunctionModbusSlaveAnswerReadHoldingRegistersRequest = 27
  • rs485_bricklet.FunctionModbusSlaveAnswerWriteSingleCoilRequest = 29
  • rs485_bricklet.FunctionModbusSlaveAnswerWriteSingleRegisterRequest = 31
  • rs485_bricklet.FunctionModbusSlaveAnswerWriteMultipleCoilsRequest = 33
  • rs485_bricklet.FunctionModbusSlaveAnswerWriteMultipleRegistersRequest = 35
  • rs485_bricklet.FunctionModbusSlaveAnswerReadDiscreteInputsRequest = 37
  • rs485_bricklet.FunctionModbusSlaveAnswerReadInputRegistersRequest = 39
  • rs485_bricklet.FunctionSetFrameReadableCallbackConfiguration = 59
  • rs485_bricklet.FunctionSetWriteFirmwarePointer = 237
  • rs485_bricklet.FunctionSetStatusLEDConfig = 239
  • rs485_bricklet.FunctionReset = 243
  • rs485_bricklet.FunctionWriteUID = 248
func (*RS485Bricklet) SetResponseExpectedAll(responseExpected bool) (err error)
Parameters:
  • responseExpected – Type: bool
Returns:
  • err – Type: error

Changes the response expected flag for all setter and callback configuration functions of this device at once.

Internal Functions

Internal functions are used for maintenance tasks such as flashing a new firmware of changing the UID of a Bricklet. These task should be performed using Brick Viewer instead of using the internal functions directly.

func (*RS485Bricklet) SetBootloaderMode(mode uint8) (status uint8, err error)
Parameters:
  • mode – Type: uint8, Range: See constants
Returns:
  • status – Type: uint8, Range: See constants
  • err – Type: error

Sets the bootloader mode and returns the status after the requested mode change was instigated.

You can change from bootloader mode to firmware mode and vice versa. A change from bootloader mode to firmware mode will only take place if the entry function, device identifier and CRC are present and correct.

This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.

The following constants are available for this function:

For mode:

  • rs485_bricklet.BootloaderModeBootloader = 0
  • rs485_bricklet.BootloaderModeFirmware = 1
  • rs485_bricklet.BootloaderModeBootloaderWaitForReboot = 2
  • rs485_bricklet.BootloaderModeFirmwareWaitForReboot = 3
  • rs485_bricklet.BootloaderModeFirmwareWaitForEraseAndReboot = 4

For status:

  • rs485_bricklet.BootloaderStatusOK = 0
  • rs485_bricklet.BootloaderStatusInvalidMode = 1
  • rs485_bricklet.BootloaderStatusNoChange = 2
  • rs485_bricklet.BootloaderStatusEntryFunctionNotPresent = 3
  • rs485_bricklet.BootloaderStatusDeviceIdentifierIncorrect = 4
  • rs485_bricklet.BootloaderStatusCRCMismatch = 5
func (*RS485Bricklet) GetBootloaderMode() (mode uint8, err error)
Returns:
  • mode – Type: uint8, Range: See constants
  • err – Type: error

Returns the current bootloader mode, see SetBootloaderMode().

The following constants are available for this function:

For mode:

  • rs485_bricklet.BootloaderModeBootloader = 0
  • rs485_bricklet.BootloaderModeFirmware = 1
  • rs485_bricklet.BootloaderModeBootloaderWaitForReboot = 2
  • rs485_bricklet.BootloaderModeFirmwareWaitForReboot = 3
  • rs485_bricklet.BootloaderModeFirmwareWaitForEraseAndReboot = 4
func (*RS485Bricklet) SetWriteFirmwarePointer(pointer uint32) (err error)
Parameters:
  • pointer – Type: uint32, Unit: 1 B, Range: [0 to 232 - 1]
Returns:
  • err – Type: error

Sets the firmware pointer for WriteFirmware(). The pointer has to be increased by chunks of size 64. The data is written to flash every 4 chunks (which equals to one page of size 256).

This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.

func (*RS485Bricklet) WriteFirmware(data [64]uint8) (status uint8, err error)
Parameters:
  • data – Type: [64]uint8, Range: [0 to 255]
Returns:
  • status – Type: uint8, Range: [0 to 255]
  • err – Type: error

Writes 64 Bytes of firmware at the position as written by SetWriteFirmwarePointer() before. The firmware is written to flash every 4 chunks.

You can only write firmware in bootloader mode.

This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.

func (*RS485Bricklet) WriteUID(uid uint32) (err error)
Parameters:
  • uid – Type: uint32, Range: [0 to 232 - 1]
Returns:
  • err – Type: error

Writes a new UID into flash. If you want to set a new UID you have to decode the Base58 encoded UID string into an integer first.

We recommend that you use Brick Viewer to change the UID.

func (*RS485Bricklet) ReadUID() (uid uint32, err error)
Returns:
  • uid – Type: uint32, Range: [0 to 232 - 1]
  • err – Type: error

Returns the current UID as an integer. Encode as Base58 to get the usual string version.

Constants

rs485_bricklet.DeviceIdentifier

This constant is used to identify a RS485 Bricklet.

The GetIdentity() function and the (*IPConnection) RegisterEnumerateCallback callback of the IPConnection have a deviceIdentifier parameter to specify the Brick's or Bricklet's type.

rs485_bricklet.DeviceDisplayName

This constant represents the human readable name of a RS485 Bricklet.