Modbus - IO-4 Bricklet

This is the description of the Modbus protocol for the IO-4 Bricklet. General information and technical specifications for the IO-4 Bricklet are summarized in its hardware description.

API

A general description of the Modbus protocol structure can be found here.

Basic Functions

BrickletIO4.set_value
Function ID:
  • 1
Request:
  • value_mask – Type: uint8, Range: [0 to 15]
Response:
  • no response

Sets the output value (high or low) with a bitmask (4bit). A 1 in the bitmask means high and a 0 in the bitmask means low.

For example: The value 3 or 0b0011 will turn the pins 0-1 high and the pins 2-3 low.

All running monoflop timers will be aborted if this function is called.

Note

This function does nothing for pins that are configured as input. Pull-up resistors can be switched on with set_configuration.

BrickletIO4.get_value
Function ID:
  • 2
Request:
  • empty payload
Response:
  • value_mask – Type: uint8, Range: [0 to 15]

Returns a bitmask of the values that are currently measured. This function works if the pin is configured to input as well as if it is configured to output.

BrickletIO4.set_configuration
Function ID:
  • 3
Request:
  • selection_mask – Type: uint8, Range: [0 to 15]
  • direction – Type: char, Range: See meanings, Default: 'i'
  • value – Type: bool, Default: true
Response:
  • no response

Configures the value and direction of the specified pins. Possible directions are 'i' and 'o' for input and output.

If the direction is configured as output, the value is either high or low (set as true or false).

If the direction is configured as input, the value is either pull-up or default (set as true or false).

For example:

  • (15, 'i', true) or (0b1111, 'i', true) will set all pins of as input pull-up.
  • (8, 'i', false) or (0b1000, 'i', false) will set pin 3 of as input default (floating if nothing is connected).
  • (3, 'o', false) or (0b0011, 'o', false) will set pins 0 and 1 as output low.
  • (4, 'o', true) or (0b0100, 'o', true) will set pin 2 of as output high.

Running monoflop timers for the specified pins will be aborted if this function is called.

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

For direction:

  • 'i' = In
  • 'o' = Out
BrickletIO4.get_configuration
Function ID:
  • 4
Request:
  • empty payload
Response:
  • direction_mask – Type: uint8, Range: [0 to 15]
  • value_mask – Type: uint8, Range: [0 to 15]

Returns a value bitmask and a direction bitmask. A 1 in the direction bitmask means input and a 0 in the bitmask means output.

For example: A return value of (3, 5) or (0b0011, 0b0101) for direction and value means that:

  • pin 0 is configured as input pull-up,
  • pin 1 is configured as input default,
  • pin 2 is configured as output high and
  • pin 3 is are configured as output low.
BrickletIO4.get_edge_count
Function ID:
  • 14
Request:
  • pin – Type: uint8, Range: [0 to 3]
  • reset_counter – Type: bool
Response:
  • count – Type: uint32, Range: [0 to 232 - 1]

Returns the current value of the edge counter for the selected pin. You can configure the edges that are counted with set_edge_count_config.

If you set the reset counter to true, the count is set back to 0 directly after it is read.

New in version 2.0.1 (Plugin).

Advanced Functions

BrickletIO4.set_monoflop
Function ID:
  • 10
Request:
  • selection_mask – Type: uint8, Range: [0 to 15]
  • value_mask – Type: uint8, Range: [0 to 15]
  • time – Type: uint32, Unit: 1 ms, Range: [0 to 232 - 1]
Response:
  • no response

Configures a monoflop of the pins specified by the first parameter as 4 bit long bitmask. The specified pins must be configured for output. Non-output pins will be ignored.

The second parameter is a bitmask with the desired value of the specified output pins. A 1 in the bitmask means high and a 0 in the bitmask means low.

The third parameter indicates the time that the pins should hold the value.

If this function is called with the parameters (9, 1, 1500) or (0b1001, 0b0001, 1500): Pin 0 will get high and pin 3 will get low. In 1.5s pin 0 will get low and pin 3 will get high again.

A monoflop can be used as a fail-safe mechanism. For example: Lets assume you have a RS485 bus and an IO-4 Bricklet connected to one of the slave stacks. You can now call this function every second, with a time parameter of two seconds and pin 0 set to high. Pin 0 will be high all the time. If now the RS485 connection is lost, then pin 0 will get low in at most two seconds.

BrickletIO4.get_monoflop
Function ID:
  • 11
Request:
  • pin – Type: uint8, Range: [0 to 3]
Response:
  • value – Type: uint8, Range: [0 to 1]
  • time – Type: uint32, Unit: 1 ms, Range: [0 to 232 - 1]
  • time_remaining – Type: uint32, Unit: 1 ms, Range: [0 to 232 - 1]

Returns (for the given pin) the current value and the time as set by set_monoflop as well as the remaining time until the value flips.

If the timer is not running currently, the remaining time will be returned as 0.

BrickletIO4.set_selected_values
Function ID:
  • 13
Request:
  • selection_mask – Type: uint8, Range: [0 to 15]
  • value_mask – Type: uint8, Range: [0 to 15]
Response:
  • no response

Sets the output value (high or low) with a bitmask, according to the selection mask. The bitmask is 4 bit long, true refers to high and false refers to low.

For example: The parameters (9, 4) or (0b0110, 0b0100) will turn pin 1 low and pin 2 high, pin 0 and 3 will remain untouched.

Running monoflop timers for the selected pins will be aborted if this function is called.

Note

This function does nothing for pins that are configured as input. Pull-up resistors can be switched on with set_configuration.

BrickletIO4.set_edge_count_config
Function ID:
  • 15
Request:
  • selection_mask – Type: uint8, Range: [0 to 15]
  • edge_type – Type: uint8, Range: See meanings, Default: 0
  • debounce – Type: uint8, Unit: 1 ms, Range: [0 to 255], Default: 100
Response:
  • no response

Configures the edge counter for the selected pins.

The edge type parameter configures if rising edges, falling edges or both are counted if the pin is configured for input. Possible edge types are:

  • 0 = rising (default)
  • 1 = falling
  • 2 = both

Configuring an edge counter resets its value to 0.

If you don't know what any of this means, just leave it at default. The default configuration is very likely OK for you.

New in version 2.0.1 (Plugin).

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

For edge_type:

  • 0 = Rising
  • 1 = Falling
  • 2 = Both
BrickletIO4.get_edge_count_config
Function ID:
  • 16
Request:
  • pin – Type: uint8, Range: [0 to 3]
Response:
  • edge_type – Type: uint8, Range: See meanings, Default: 0
  • debounce – Type: uint8, Unit: 1 ms, Range: [0 to 255], Default: 100

Returns the edge type and debounce time for the selected pin as set by set_edge_count_config.

New in version 2.0.1 (Plugin).

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

For edge_type:

  • 0 = Rising
  • 1 = Falling
  • 2 = Both
BrickletIO4.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

BrickletIO4.set_debounce_period
Function ID:
  • 5
Request:
  • debounce – Type: uint32, Unit: 1 ms, Range: [0 to 232 - 1], Default: 100
Response:
  • no response

Sets the debounce period of the CALLBACK_INTERRUPT callback.

For example: If you set this value to 100, you will get the interrupt maximal every 100ms. This is necessary if something that bounces is connected to the IO-4 Bricklet, such as a button.

BrickletIO4.get_debounce_period
Function ID:
  • 6
Request:
  • empty payload
Response:
  • debounce – Type: uint32, Unit: 1 ms, Range: [0 to 232 - 1], Default: 100

Returns the debounce period as set by set_debounce_period.

BrickletIO4.set_interrupt
Function ID:
  • 7
Request:
  • interrupt_mask – Type: uint8, Range: [0 to 15]
Response:
  • no response

Sets the pins on which an interrupt is activated with a bitmask. Interrupts are triggered on changes of the voltage level of the pin, i.e. changes from high to low and low to high.

For example: An interrupt bitmask of 10 or 0b1010 will enable the interrupt for pins 1 and 3.

The interrupt is delivered with the CALLBACK_INTERRUPT callback.

BrickletIO4.get_interrupt
Function ID:
  • 8
Request:
  • empty payload
Response:
  • interrupt_mask – Type: uint8, Range: [0 to 15]

Returns the interrupt bitmask as set by set_interrupt.

Callbacks

BrickletIO4.CALLBACK_INTERRUPT
Function ID:
  • 9
Response:
  • interrupt_mask – Type: uint8, Range: [0 to 15]
  • value_mask – Type: uint8, Range: [0 to 15]

This callback is triggered whenever a change of the voltage level is detected on pins where the interrupt was activated with set_interrupt.

The values are a bitmask that specifies which interrupts occurred and the current value bitmask.

For example:

  • (1, 1) or (0b0001, 0b0001) means that an interrupt on pin 0 occurred and currently pin 0 is high and pins 1-3 are low.
  • (9, 14) or (0b1001, 0b1110) means that interrupts on pins 0 and 3 occurred and currently pin 0 is low and pins 1-3 are high.
BrickletIO4.CALLBACK_MONOFLOP_DONE
Function ID:
  • 12
Response:
  • selection_mask – Type: uint8, Range: [0 to 15]
  • value_mask – Type: uint8, Range: [0 to 15]

This callback is triggered whenever a monoflop timer reaches 0. The response values contain the involved pins and the current value of the pins (the value after the monoflop).