Modbus - RS485 Bricklet¶

Basic Functions¶

BrickletRS485.write_low_level¶

Function ID:	1
Request:	message_length – Type: uint16, Range: [0 to 216 - 1] message_chunk_offset – Type: uint16, Range: [0 to 216 - 1] message_chunk_data – Type: char[60]
Response:	message_chunk_written – Type: uint8, Range: [0 to 255]

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 set_rs485_configuration for configuration possibilities regarding baudrate, parity and so on.

BrickletRS485.read_low_level¶

Function ID:	2
Request:	length – Type: uint16, Range: [0 to 216 - 1]
Response:	message_length – Type: uint16, Range: [0 to 216 - 1] message_chunk_offset – Type: uint16, Range: [0 to 216 - 1] message_chunk_data – Type: char[60]

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 enable_read_callback and CALLBACK_READ_LOW_LEVEL callback.

BrickletRS485.set_rs485_configuration¶

Function ID:	6
Request:	baudrate – Type: uint32, Unit: 1 Bd, Range: [100 to 2000000], Default: 115200 parity – Type: uint8, Range: See meanings, Default: 0 stopbits – Type: uint8, Range: See meanings, Default: 1 wordlength – Type: uint8, Range: See meanings, Default: 8 duplex – Type: uint8, Range: See meanings, Default: 0
Response:	no response

Sets the configuration for the RS485 communication.

The following meanings are defined for the elements of this function:

For parity:

• 0 = None
• 1 = Odd
• 2 = Even

For stopbits:

• 1 = 1
• 2 = 2

For wordlength:

• 5 = 5
• 6 = 6
• 7 = 7
• 8 = 8

For duplex:

• 0 = Half
• 1 = Full

BrickletRS485.get_rs485_configuration¶

Function ID:	7
Request:	empty payload
Response:	baudrate – Type: uint32, Unit: 1 Bd, Range: [100 to 2000000], Default: 115200 parity – Type: uint8, Range: See meanings, Default: 0 stopbits – Type: uint8, Range: See meanings, Default: 1 wordlength – Type: uint8, Range: See meanings, Default: 8 duplex – Type: uint8, Range: See meanings, Default: 0

Returns the configuration as set by set_rs485_configuration.

The following meanings are defined for the elements of this function:

For parity:

• 0 = None
• 1 = Odd
• 2 = Even

For stopbits:

• 1 = 1
• 2 = 2

For wordlength:

• 5 = 5
• 6 = 6
• 7 = 7
• 8 = 8

For duplex:

• 0 = Half
• 1 = Full

BrickletRS485.set_modbus_configuration¶

Function ID:	8
Request:	slave_address – Type: uint8, Range: [1 to 247], Default: 1 master_request_timeout – Type: uint32, Unit: 1 ms, Range: [0 to 232 - 1], Default: 1000
Response:	no response

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.

BrickletRS485.get_modbus_configuration¶

Function ID:	9
Request:	empty payload
Response:	slave_address – Type: uint8, Range: [1 to 247], Default: 1 master_request_timeout – Type: uint32, Unit: 1 ms, Range: [0 to 232 - 1], Default: 1000

Returns the configuration as set by set_modbus_configuration.

BrickletRS485.set_mode¶

Function ID:	10
Request:	mode – Type: uint8, Range: See meanings, Default: 0
Response:	no response

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

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

The following meanings are defined for the elements of this function:

For mode:

• 0 = RS485
• 1 = Modbus Master RTU
• 2 = Modbus Slave RTU

BrickletRS485.get_mode¶

Function ID:	11
Request:	empty payload
Response:	mode – Type: uint8, Range: See meanings, Default: 0

Returns the configuration as set by set_mode.

The following meanings are defined for the elements of this function:

For mode:

• 0 = RS485
• 1 = Modbus Master RTU
• 2 = Modbus Slave RTU

Advanced Functions¶

BrickletRS485.set_communication_led_config¶

Function ID:	12
Request:	config – Type: uint8, Range: See meanings, Default: 3
Response:	no response

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 meanings are defined for the elements of this function:

For config:

• 0 = Off
• 1 = On
• 2 = Show Heartbeat
• 3 = Show Communication

BrickletRS485.get_communication_led_config¶

Function ID:	13
Request:	empty payload
Response:	config – Type: uint8, Range: See meanings, Default: 3

Returns the configuration as set by set_communication_led_config

The following meanings are defined for the elements of this function:

For config:

• 0 = Off
• 1 = On
• 2 = Show Heartbeat
• 3 = Show Communication

BrickletRS485.set_error_led_config¶

Function ID:	14
Request:	config – Type: uint8, Range: See meanings, Default: 3
Response:	no response

Sets the error LED configuration.

By default the error LED turns on if there is any error (see CALLBACK_ERROR_COUNT 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 meanings are defined for the elements of this function:

For config:

• 0 = Off
• 1 = On
• 2 = Show Heartbeat
• 3 = Show Error

BrickletRS485.get_error_led_config¶

Function ID:	15
Request:	empty payload
Response:	config – Type: uint8, Range: See meanings, Default: 3

Returns the configuration as set by set_error_led_config.

The following meanings are defined for the elements of this function:

For config:

• 0 = Off
• 1 = On
• 2 = Show Heartbeat
• 3 = Show Error

BrickletRS485.set_buffer_config¶

Function ID:	16
Request:	send_buffer_size – Type: uint16, Unit: 1 B, Range: [210 to 9216], Default: 5120 receive_buffer_size – Type: uint16, Unit: 1 B, Range: [210 to 9216], Default: 5120
Response:	no response

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_low_level 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_low_level or through CALLBACK_READ_LOW_LEVEL callback.

BrickletRS485.get_buffer_config¶

Function ID:	17
Request:	empty payload
Response:	send_buffer_size – Type: uint16, Unit: 1 B, Range: [210 to 9216], Default: 5120 receive_buffer_size – Type: uint16, Unit: 1 B, Range: [210 to 9216], Default: 5120

Returns the buffer configuration as set by set_buffer_config.

BrickletRS485.get_buffer_status¶

Function ID:	18
Request:	empty payload
Response:	send_buffer_used – Type: uint16, Unit: 1 B, Range: [0 to 9216] receive_buffer_used – Type: uint16, Unit: 1 B, Range: [0 to 9216]

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

See set_buffer_config for buffer size configuration.

BrickletRS485.get_error_count¶

Function ID:	22
Request:	empty payload
Response:	overrun_error_count – Type: uint32, Range: [0 to 232 - 1] parity_error_count – Type: uint32, Range: [0 to 232 - 1]

Returns the current number of overrun and parity errors.

BrickletRS485.get_modbus_common_error_count¶

Function ID:	23
Request:	empty payload
Response:	timeout_error_count – Type: uint32, Range: [0 to 232 - 1] checksum_error_count – Type: uint32, Range: [0 to 232 - 1] frame_too_big_error_count – Type: uint32, Range: [0 to 232 - 1] illegal_function_error_count – Type: uint32, Range: [0 to 232 - 1] illegal_data_address_error_count – Type: uint32, Range: [0 to 232 - 1] illegal_data_value_error_count – Type: uint32, Range: [0 to 232 - 1] slave_device_failure_error_count – Type: uint32, Range: [0 to 232 - 1]

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.

BrickletRS485.modbus_slave_report_exception¶

Function ID:	24
Request:	request_id – Type: uint8, Range: [0 to 255] exception_code – Type: int8, Range: See meanings
Response:	no response

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 meanings are defined for the elements of this function:

For exception_code:

• -1 = Timeout
• 0 = Success
• 1 = Illegal Function
• 2 = Illegal Data Address
• 3 = Illegal Data Value
• 4 = Slave Device Failure
• 5 = Acknowledge
• 6 = Slave Device Busy
• 8 = Memory Parity Error
• 10 = Gateway Path Unavailable
• 11 = Gateway Target Device Failed To Respond

BrickletRS485.modbus_slave_answer_read_coils_request_low_level¶

Function ID:	25
Request:	request_id – Type: uint8, Range: [0 to 255] coils_length – Type: uint16, Range: [1 to 2000] coils_chunk_offset – Type: uint16, Range: [0 to 216 - 1] coils_chunk_data – Type: bool[472]
Response:	no response

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 CALLBACK_MODBUS_SLAVE_READ_COILS_REQUEST callback with the Request ID as provided by the argument of the callback.

BrickletRS485.modbus_master_read_coils¶

Function ID:	26
Request:	slave_address – Type: uint8, Range: [0 to 247] starting_address – Type: uint32, Range: [1 to 216] count – Type: uint16, Range: [1 to 2000]
Response:	request_id – Type: uint8, Range: [0 to 255]

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 CALLBACK_MODBUS_MASTER_READ_COILS_RESPONSE_LOW_LEVEL 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.

BrickletRS485.modbus_slave_answer_read_holding_registers_request_low_level¶

Function ID:	27
Request:	request_id – Type: uint8, Range: [0 to 255] holding_registers_length – Type: uint16, Range: [1 to 125] holding_registers_chunk_offset – Type: uint16, Range: [0 to 216 - 1] holding_registers_chunk_data – Type: uint16[29], Range: [0 to 216 - 1]
Response:	no response

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 CALLBACK_MODBUS_SLAVE_READ_HOLDING_REGISTERS_REQUEST callback with the Request ID as provided by the argument of the callback.

BrickletRS485.modbus_master_read_holding_registers¶

Function ID:	28
Request:	slave_address – Type: uint8, Range: [0 to 247] starting_address – Type: uint32, Range: [1 to 216] count – Type: uint16, Range: [1 to 125]
Response:	request_id – Type: uint8, Range: [0 to 255]

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 CALLBACK_MODBUS_MASTER_READ_HOLDING_REGISTERS_RESPONSE_LOW_LEVEL 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.

BrickletRS485.modbus_slave_answer_write_single_coil_request¶

Function ID:	29
Request:	request_id – Type: uint8, Range: [0 to 255]
Response:	no response

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 CALLBACK_MODBUS_SLAVE_WRITE_SINGLE_COIL_REQUEST callback with the Request ID as provided by the arguments of the callback.

BrickletRS485.modbus_master_write_single_coil¶

Function ID:	30
Request:	slave_address – Type: uint8, Range: [0 to 247] coil_address – Type: uint32, Range: [1 to 216] coil_value – Type: bool
Response:	request_id – Type: uint8, Range: [0 to 255]

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 CALLBACK_MODBUS_MASTER_WRITE_SINGLE_COIL_RESPONSE 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.

BrickletRS485.modbus_slave_answer_write_single_register_request¶

Function ID:	31
Request:	request_id – Type: uint8, Range: [0 to 255]
Response:	no response

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 CALLBACK_MODBUS_SLAVE_WRITE_SINGLE_REGISTER_REQUEST callback with the Request ID, Register Address and Register Value as provided by the arguments of the callback.

BrickletRS485.modbus_master_write_single_register¶

Function ID:	32
Request:	slave_address – Type: uint8, Range: [0 to 247] register_address – Type: uint32, Range: [1 to 216] register_value – Type: uint16, Range: [0 to 216 - 1]
Response:	request_id – Type: uint8, Range: [0 to 255]

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 CALLBACK_MODBUS_MASTER_WRITE_SINGLE_REGISTER_RESPONSE 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.

BrickletRS485.modbus_slave_answer_write_multiple_coils_request¶

Function ID:	33
Request:	request_id – Type: uint8, Range: [0 to 255]
Response:	no response

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 CALLBACK_MODBUS_SLAVE_WRITE_MULTIPLE_COILS_REQUEST_LOW_LEVEL callback with the Request ID of the callback.

BrickletRS485.modbus_master_write_multiple_coils_low_level¶

Function ID:	34
Request:	slave_address – Type: uint8, Range: [0 to 247] starting_address – Type: uint32, Range: [1 to 216] coils_length – Type: uint16, Range: [1 to 1968] coils_chunk_offset – Type: uint16, Range: [0 to 216 - 1] coils_chunk_data – Type: bool[440]
Response:	request_id – Type: uint8, Range: [0 to 255]

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 CALLBACK_MODBUS_MASTER_WRITE_MULTIPLE_COILS_RESPONSE 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.

BrickletRS485.modbus_slave_answer_write_multiple_registers_request¶

Function ID:	35
Request:	request_id – Type: uint8, Range: [0 to 255]
Response:	no response

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 CALLBACK_MODBUS_SLAVE_WRITE_MULTIPLE_REGISTERS_REQUEST_LOW_LEVEL callback with the Request ID of the callback.

BrickletRS485.modbus_master_write_multiple_registers_low_level¶

Function ID:	36
Request:	slave_address – Type: uint8, Range: [0 to 247] starting_address – Type: uint32, Range: [1 to 216] registers_length – Type: uint16, Range: [1 to 123] registers_chunk_offset – Type: uint16, Range: [0 to 216 - 1] registers_chunk_data – Type: uint16[27], Range: [0 to 216 - 1]
Response:	request_id – Type: uint8, Range: [0 to 255]

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 CALLBACK_MODBUS_MASTER_WRITE_MULTIPLE_REGISTERS_RESPONSE 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.

BrickletRS485.modbus_slave_answer_read_discrete_inputs_request_low_level¶

Function ID:	37
Request:	request_id – Type: uint8, Range: [0 to 255] discrete_inputs_length – Type: uint16, Range: [1 to 2000] discrete_inputs_chunk_offset – Type: uint16, Range: [0 to 216 - 1] discrete_inputs_chunk_data – Type: bool[472]
Response:	no response

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 CALLBACK_MODBUS_SLAVE_READ_DISCRETE_INPUTS_REQUEST callback with the Request ID as provided by the argument of the callback.

BrickletRS485.modbus_master_read_discrete_inputs¶

Function ID:	38
Request:	slave_address – Type: uint8, Range: [0 to 247] starting_address – Type: uint32, Range: [1 to 216] count – Type: uint16, Range: [1 to 2000]
Response:	request_id – Type: uint8, Range: [0 to 255]

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 CALLBACK_MODBUS_MASTER_READ_DISCRETE_INPUTS_RESPONSE_LOW_LEVEL 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.

BrickletRS485.modbus_slave_answer_read_input_registers_request_low_level¶

Function ID:	39
Request:	request_id – Type: uint8, Range: [0 to 255] input_registers_length – Type: uint16, Range: [1 to 125] input_registers_chunk_offset – Type: uint16, Range: [0 to 216 - 1] input_registers_chunk_data – Type: uint16[29], Range: [0 to 216 - 1]
Response:	no response

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 CALLBACK_MODBUS_SLAVE_READ_INPUT_REGISTERS_REQUEST callback with the Request ID as provided by the argument of the callback.

BrickletRS485.modbus_master_read_input_registers¶

Function ID:	40
Request:	slave_address – Type: uint8, Range: [0 to 247] starting_address – Type: uint32, Range: [1 to 216] count – Type: uint16, Range: [1 to 125]
Response:	request_id – Type: uint8, Range: [0 to 255]

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 CALLBACK_MODBUS_MASTER_READ_INPUT_REGISTERS_RESPONSE_LOW_LEVEL 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.

BrickletRS485.get_spitfp_error_count¶

Function ID:	234
Request:	empty payload
Response:	error_count_ack_checksum – Type: uint32, Range: [0 to 232 - 1] error_count_message_checksum – Type: uint32, Range: [0 to 232 - 1] error_count_frame – Type: uint32, Range: [0 to 232 - 1] error_count_overflow – Type: uint32, Range: [0 to 232 - 1]

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.

BrickletRS485.set_status_led_config¶

Function ID:	239
Request:	config – Type: uint8, Range: See meanings, Default: 3
Response:	no response

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 meanings are defined for the elements of this function:

For config:

• 0 = Off
• 1 = On
• 2 = Show Heartbeat
• 3 = Show Status

BrickletRS485.get_status_led_config¶

Function ID:	240
Request:	empty payload
Response:	config – Type: uint8, Range: See meanings, Default: 3

Returns the configuration as set by set_status_led_config

The following meanings are defined for the elements of this function:

For config:

• 0 = Off
• 1 = On
• 2 = Show Heartbeat
• 3 = Show Status

BrickletRS485.get_chip_temperature¶

Function ID:	242
Request:	empty payload
Response:	temperature – Type: int16, Unit: 1 °C, Range: [-215 to 215 - 1]

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.

BrickletRS485.reset¶

Function ID:	243
Request:	empty payload
Response:	no response

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!

BrickletRS485.get_identity¶

Function ID:	255
Request:	empty payload
Response:	uid – Type: char[8] connected_uid – Type: char[8] position – Type: char, Range: ['a' to 'h', 'z'] hardware_version – Type: uint8[3] 0: major – Type: uint8, Range: [0 to 255] 1: minor – Type: uint8, Range: [0 to 255] 2: revision – Type: uint8, Range: [0 to 255] firmware_version – Type: uint8[3] 0: major – Type: uint8, Range: [0 to 255] 1: minor – Type: uint8, Range: [0 to 255] 2: revision – Type: uint8, Range: [0 to 255] device_identifier – Type: uint16, Range: [0 to 216 - 1]

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. 

Callback Configuration Functions¶

BrickletRS485.enable_read_callback¶

Function ID:	3
Request:	empty payload
Response:	no response

Enables the CALLBACK_READ_LOW_LEVEL callback. This will disable the CALLBACK_FRAME_READABLE callback.

By default the callback is disabled.

BrickletRS485.disable_read_callback¶

Function ID:	4
Request:	empty payload
Response:	no response

Disables the CALLBACK_READ_LOW_LEVEL callback.

By default the callback is disabled.

BrickletRS485.is_read_callback_enabled¶

Function ID:	5
Request:	empty payload
Response:	enabled – Type: bool, Default: false

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

BrickletRS485.enable_error_count_callback¶

Function ID:	19
Request:	empty payload
Response:	no response

Enables the CALLBACK_ERROR_COUNT callback.

By default the callback is disabled.

BrickletRS485.disable_error_count_callback¶

Function ID:	20
Request:	empty payload
Response:	no response

Disables the CALLBACK_ERROR_COUNT callback.

By default the callback is disabled.

BrickletRS485.is_error_count_callback_enabled¶

Function ID:	21
Request:	empty payload
Response:	enabled – Type: bool, Default: true

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

BrickletRS485.set_frame_readable_callback_configuration¶

Function ID:	59
Request:	frame_size – Type: uint16, Unit: 1 B, Range: [0 to 9216], Default: 0
Response:	no response

Configures the CALLBACK_FRAME_READABLE 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 CALLBACK_READ_LOW_LEVEL callback.

By default the callback is disabled.

New in version 2.0.5 (Plugin).

BrickletRS485.get_frame_readable_callback_configuration¶

Function ID:	60
Request:	empty payload
Response:	frame_size – Type: uint16, Unit: 1 B, Range: [0 to 9216], Default: 0

Returns the callback configuration as set by set_frame_readable_callback_configuration.

New in version 2.0.5 (Plugin).

Callbacks¶

BrickletRS485.CALLBACK_READ_LOW_LEVEL¶

Function ID:	41
Response:	message_length – Type: uint16, Range: [0 to 216 - 1] message_chunk_offset – Type: uint16, Range: [0 to 216 - 1] message_chunk_data – Type: char[60]

This callback is called if new data is available.

To enable this callback, use enable_read_callback.

BrickletRS485.CALLBACK_ERROR_COUNT¶

Function ID:	42
Response:	overrun_error_count – Type: uint32, Range: [0 to 232 - 1] parity_error_count – Type: uint32, Range: [0 to 232 - 1]

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

BrickletRS485.CALLBACK_MODBUS_SLAVE_READ_COILS_REQUEST¶

Function ID:	43
Response:	request_id – Type: uint8, Range: [0 to 255] starting_address – Type: uint32, Range: [1 to 216] count – Type: uint16, Range: [1 to 2000]

This callback is called only in Modbus slave mode when the slave receives a valid request from a Modbus master to read coils. The response values 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 modbus_slave_answer_read_coils_request_low_level.

BrickletRS485.CALLBACK_MODBUS_MASTER_READ_COILS_RESPONSE_LOW_LEVEL¶

Function ID:	44
Response:	request_id – Type: uint8, Range: [0 to 255] exception_code – Type: int8, Range: See meanings coils_length – Type: uint16, Range: [0 to 2000] coils_chunk_offset – Type: uint16, Range: [0 to 216 - 1] coils_chunk_data – Type: bool[464]

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

The response values 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 set_modbus_configuration.

The following meanings are defined for the elements of this function:

For exception_code:

• -1 = Timeout
• 0 = Success
• 1 = Illegal Function
• 2 = Illegal Data Address
• 3 = Illegal Data Value
• 4 = Slave Device Failure
• 5 = Acknowledge
• 6 = Slave Device Busy
• 8 = Memory Parity Error
• 10 = Gateway Path Unavailable
• 11 = Gateway Target Device Failed To Respond

BrickletRS485.CALLBACK_MODBUS_SLAVE_READ_HOLDING_REGISTERS_REQUEST¶

Function ID:	45
Response:	request_id – Type: uint8, Range: [0 to 255] starting_address – Type: uint32, Range: [1 to 216] count – Type: uint16, Range: [1 to 125]

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 response values 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 modbus_slave_answer_read_holding_registers_request_low_level.

BrickletRS485.CALLBACK_MODBUS_MASTER_READ_HOLDING_REGISTERS_RESPONSE_LOW_LEVEL¶

Function ID:	46
Response:	request_id – Type: uint8, Range: [0 to 255] exception_code – Type: int8, Range: See meanings holding_registers_length – Type: uint16, Range: [0 to 125] holding_registers_chunk_offset – Type: uint16, Range: [0 to 216 - 1] holding_registers_chunk_data – Type: uint16[29], Range: [0 to 216 - 1]

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

The response values 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 set_modbus_configuration.

The following meanings are defined for the elements of this function:

For exception_code:

• -1 = Timeout
• 0 = Success
• 1 = Illegal Function
• 2 = Illegal Data Address
• 3 = Illegal Data Value
• 4 = Slave Device Failure
• 5 = Acknowledge
• 6 = Slave Device Busy
• 8 = Memory Parity Error
• 10 = Gateway Path Unavailable
• 11 = Gateway Target Device Failed To Respond

BrickletRS485.CALLBACK_MODBUS_SLAVE_WRITE_SINGLE_COIL_REQUEST¶

Function ID:	47
Response:	request_id – Type: uint8, Range: [0 to 255] coil_address – Type: uint32, Range: [1 to 216] coil_value – Type: bool

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 response values 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 modbus_slave_answer_write_single_coil_request.

BrickletRS485.CALLBACK_MODBUS_MASTER_WRITE_SINGLE_COIL_RESPONSE¶

Function ID:	48
Response:	request_id – Type: uint8, Range: [0 to 255] exception_code – Type: int8, Range: See meanings

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 response values 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 set_modbus_configuration.

The following meanings are defined for the elements of this function:

For exception_code:

• -1 = Timeout
• 0 = Success
• 1 = Illegal Function
• 2 = Illegal Data Address
• 3 = Illegal Data Value
• 4 = Slave Device Failure
• 5 = Acknowledge
• 6 = Slave Device Busy
• 8 = Memory Parity Error
• 10 = Gateway Path Unavailable
• 11 = Gateway Target Device Failed To Respond

BrickletRS485.CALLBACK_MODBUS_SLAVE_WRITE_SINGLE_REGISTER_REQUEST¶

Function ID:	49
Response:	request_id – Type: uint8, Range: [0 to 255] register_address – Type: uint32, Range: [1 to 216] register_value – Type: uint16, Range: [0 to 216 - 1]

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 response values 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 modbus_slave_answer_write_single_register_request.

BrickletRS485.CALLBACK_MODBUS_MASTER_WRITE_SINGLE_REGISTER_RESPONSE¶

Function ID:	50
Response:	request_id – Type: uint8, Range: [0 to 255] exception_code – Type: int8, Range: See meanings

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 response values 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 set_modbus_configuration.

The following meanings are defined for the elements of this function:

For exception_code:

• -1 = Timeout
• 0 = Success
• 1 = Illegal Function
• 2 = Illegal Data Address
• 3 = Illegal Data Value
• 4 = Slave Device Failure
• 5 = Acknowledge
• 6 = Slave Device Busy
• 8 = Memory Parity Error
• 10 = Gateway Path Unavailable
• 11 = Gateway Target Device Failed To Respond

BrickletRS485.CALLBACK_MODBUS_SLAVE_WRITE_MULTIPLE_COILS_REQUEST_LOW_LEVEL¶

Function ID:	51
Response:	request_id – Type: uint8, Range: [0 to 255] starting_address – Type: uint32, Range: [1 to 216] coils_length – Type: uint16, Range: [1 to 1968] coils_chunk_offset – Type: uint16, Range: [0 to 216 - 1] coils_chunk_data – Type: bool[440]

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 response values 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 modbus_slave_answer_write_multiple_coils_request.

BrickletRS485.CALLBACK_MODBUS_MASTER_WRITE_MULTIPLE_COILS_RESPONSE¶

Function ID:	52
Response:	request_id – Type: uint8, Range: [0 to 255] exception_code – Type: int8, Range: See meanings

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

The response values 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 set_modbus_configuration.

The following meanings are defined for the elements of this function:

For exception_code:

• -1 = Timeout
• 0 = Success
• 1 = Illegal Function
• 2 = Illegal Data Address
• 3 = Illegal Data Value
• 4 = Slave Device Failure
• 5 = Acknowledge
• 6 = Slave Device Busy
• 8 = Memory Parity Error
• 10 = Gateway Path Unavailable
• 11 = Gateway Target Device Failed To Respond

BrickletRS485.CALLBACK_MODBUS_SLAVE_WRITE_MULTIPLE_REGISTERS_REQUEST_LOW_LEVEL¶

Function ID:	53
Response:	request_id – Type: uint8, Range: [0 to 255] starting_address – Type: uint32, Range: [1 to 216] registers_length – Type: uint16, Range: [1 to 123] registers_chunk_offset – Type: uint16, Range: [0 to 216 - 1] registers_chunk_data – Type: uint16[27], Range: [0 to 216 - 1]

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 response values 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 modbus_slave_answer_write_multiple_registers_request.

BrickletRS485.CALLBACK_MODBUS_MASTER_WRITE_MULTIPLE_REGISTERS_RESPONSE¶

Function ID:	54
Response:	request_id – Type: uint8, Range: [0 to 255] exception_code – Type: int8, Range: See meanings

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

The response values 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 set_modbus_configuration.

The following meanings are defined for the elements of this function:

For exception_code:

• -1 = Timeout
• 0 = Success
• 1 = Illegal Function
• 2 = Illegal Data Address
• 3 = Illegal Data Value
• 4 = Slave Device Failure
• 5 = Acknowledge
• 6 = Slave Device Busy
• 8 = Memory Parity Error
• 10 = Gateway Path Unavailable
• 11 = Gateway Target Device Failed To Respond

BrickletRS485.CALLBACK_MODBUS_SLAVE_READ_DISCRETE_INPUTS_REQUEST¶

Function ID:	55
Response:	request_id – Type: uint8, Range: [0 to 255] starting_address – Type: uint32, Range: [1 to 216] count – Type: uint16, Range: [1 to 2000]

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 response values 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 modbus_slave_answer_read_discrete_inputs_request_low_level.

BrickletRS485.CALLBACK_MODBUS_MASTER_READ_DISCRETE_INPUTS_RESPONSE_LOW_LEVEL¶

Function ID:	56
Response:	request_id – Type: uint8, Range: [0 to 255] exception_code – Type: int8, Range: See meanings discrete_inputs_length – Type: uint16, Range: [1 to 2000] discrete_inputs_chunk_offset – Type: uint16, Range: [0 to 216 - 1] discrete_inputs_chunk_data – Type: bool[464]

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

The response values 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 set_modbus_configuration.

The following meanings are defined for the elements of this function:

For exception_code:

• -1 = Timeout
• 0 = Success
• 1 = Illegal Function
• 2 = Illegal Data Address
• 3 = Illegal Data Value
• 4 = Slave Device Failure
• 5 = Acknowledge
• 6 = Slave Device Busy
• 8 = Memory Parity Error
• 10 = Gateway Path Unavailable
• 11 = Gateway Target Device Failed To Respond

BrickletRS485.CALLBACK_MODBUS_SLAVE_READ_INPUT_REGISTERS_REQUEST¶

Function ID:	57
Response:	request_id – Type: uint8, Range: [0 to 255] starting_address – Type: uint32, Range: [1 to 216] count – Type: uint16, Range: [1 to 125]

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 response values 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 modbus_slave_answer_read_input_registers_request_low_level.

BrickletRS485.CALLBACK_MODBUS_MASTER_READ_INPUT_REGISTERS_RESPONSE_LOW_LEVEL¶

Function ID:	58
Response:	request_id – Type: uint8, Range: [0 to 255] exception_code – Type: int8, Range: See meanings input_registers_length – Type: uint16, Range: [1 to 125] input_registers_chunk_offset – Type: uint16, Range: [0 to 216 - 1] input_registers_chunk_data – Type: uint16[29], Range: [0 to 216 - 1]

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

The response values 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 set_modbus_configuration.

The following meanings are defined for the elements of this function:

For exception_code:

• -1 = Timeout
• 0 = Success
• 1 = Illegal Function
• 2 = Illegal Data Address
• 3 = Illegal Data Value
• 4 = Slave Device Failure
• 5 = Acknowledge
• 6 = Slave Device Busy
• 8 = Memory Parity Error
• 10 = Gateway Path Unavailable
• 11 = Gateway Target Device Failed To Respond

BrickletRS485.CALLBACK_FRAME_READABLE¶

Function ID:	61
Response:	frame_count – Type: uint16, Range: [0 to 216 - 1]

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

New in version 2.0.5 (Plugin).

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.

BrickletRS485.set_bootloader_mode¶

Function ID:	235
Request:	mode – Type: uint8, Range: See meanings
Response:	status – Type: uint8, Range: See meanings

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 meanings are defined for the elements of this function:

For mode:

• 0 = Bootloader
• 1 = Firmware
• 2 = Bootloader Wait For Reboot
• 3 = Firmware Wait For Reboot
• 4 = Firmware Wait For Erase And Reboot

For status:

• 0 = OK
• 1 = Invalid Mode
• 2 = No Change
• 3 = Entry Function Not Present
• 4 = Device Identifier Incorrect
• 5 = CRC Mismatch

BrickletRS485.get_bootloader_mode¶

Function ID:	236
Request:	empty payload
Response:	mode – Type: uint8, Range: See meanings

Returns the current bootloader mode, see set_bootloader_mode.

The following meanings are defined for the elements of this function:

For mode:

• 0 = Bootloader
• 1 = Firmware
• 2 = Bootloader Wait For Reboot
• 3 = Firmware Wait For Reboot
• 4 = Firmware Wait For Erase And Reboot

BrickletRS485.set_write_firmware_pointer¶

Function ID:	237
Request:	pointer – Type: uint32, Unit: 1 B, Range: [0 to 232 - 1]
Response:	no response

Sets the firmware pointer for write_firmware. 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.

BrickletRS485.write_firmware¶

Function ID:	238
Request:	data – Type: uint8[64], Range: [0 to 255]
Response:	status – Type: uint8, Range: [0 to 255]

Writes 64 Bytes of firmware at the position as written by set_write_firmware_pointer 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.

BrickletRS485.write_uid¶

Function ID:	248
Request:	uid – Type: uint32, Range: [0 to 232 - 1]
Response:	no response

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.

BrickletRS485.read_uid¶

Function ID:	249
Request:	empty payload
Response:	uid – Type: uint32, Range: [0 to 232 - 1]

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