MQTT - Industrial Digital In 4 Bricklet

This is the description of the MQTT API bindings for the Industrial Digital In 4 Bricklet. General information and technical specifications for the Industrial Digital In 4 Bricklet are summarized in its hardware description.

An installation guide for the MQTT API bindings is part of their general description.

Examples

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

Simple

Download (example-simple.txt)

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# Change XYZ to the UID of your Industrial Digital In 4 Bricklet

setup:
    # Get current value as bitmask
    subscribe to tinkerforge/response/industrial_digital_in_4_bricklet/XYZ/get_value
    publish '' to tinkerforge/request/industrial_digital_in_4_bricklet/XYZ/get_value

Interrupt

Download (example-interrupt.txt)

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# Change XYZ to the UID of your Industrial Digital In 4 Bricklet

setup:
    # Handle incoming interrupt callbacks
    subscribe to tinkerforge/callback/industrial_digital_in_4_bricklet/XYZ/interrupt
    publish '{"register": true}' to tinkerforge/register/industrial_digital_in_4_bricklet/XYZ/interrupt # Register interrupt callback

    # Enable interrupt on pin 0: 1 << 0 = 1
    publish '{"interrupt_mask": 1}' to tinkerforge/request/industrial_digital_in_4_bricklet/XYZ/set_interrupt

API

All published payloads to and from the MQTT bindings are in JSON format.

If an error occures, the bindings publish a JSON object containing the error message as member _ERROR. It is published on the corresponding response topic: .../response/... for .../request/... and .../callback/... for .../register/....

Basic Functions

request/industrial_digital_in_4_bricklet/<UID>/get_value
Request:
  • empty payload
Response:
  • value_mask – Type: int, Range: [0 to 216 - 1]

Returns the input value with a bitmask. The bitmask is 16bit long, true refers to high and false refers to low.

For example: The value 3 or 0b0011 means that pins 0-1 are high and the other pins are low.

If no groups are used (see request/industrial_digital_in_4_bricklet/<UID>/set_group), the pins correspond to the markings on the IndustrialDigital In 4 Bricklet.

If groups are used, the pins correspond to the element in the group. Element 1 in the group will get pins 0-3, element 2 pins 4-7, element 3 pins 8-11 and element 4 pins 12-15.

request/industrial_digital_in_4_bricklet/<UID>/get_edge_count
Request:
  • pin – Type: int, Range: [0 to 3]
  • reset_counter – Type: bool
Response:
  • count – Type: int, 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 request/industrial_digital_in_4_bricklet/<UID>/set_edge_count_config.

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

The edge counters use the grouping as set by request/industrial_digital_in_4_bricklet/<UID>/set_group.

New in version 2.0.1 (Plugin).

Advanced Functions

request/industrial_digital_in_4_bricklet/<UID>/set_group
Request:
  • group – Type: [char, ...], Length: 4, Range: ["a" to "d", "n"]
Response:
  • no response

Sets a group of Digital In 4 Bricklets that should work together. You can find Bricklets that can be grouped together with request/industrial_digital_in_4_bricklet/<UID>/get_available_for_group.

The group consists of 4 elements. Element 1 in the group will get pins 0-3, element 2 pins 4-7, element 3 pins 8-11 and element 4 pins 12-15.

Each element can either be one of the ports ('a' to 'd') or 'n' if it should not be used.

For example: If you have two Digital In 4 Bricklets connected to port A and port B respectively, you could call with ['a', 'b', 'n', 'n'].

Now the pins on the Digital In 4 on port A are assigned to 0-3 and the pins on the Digital In 4 on port B are assigned to 4-7. It is now possible to call request/industrial_digital_in_4_bricklet/<UID>/get_value and read out two Bricklets at the same time.

Changing the group configuration resets all edge counter configurations and values.

request/industrial_digital_in_4_bricklet/<UID>/get_group
Request:
  • empty payload
Response:
  • group – Type: [char, ...], Length: 4, Range: ["a" to "d", "n"]

Returns the group as set by request/industrial_digital_in_4_bricklet/<UID>/set_group

request/industrial_digital_in_4_bricklet/<UID>/get_available_for_group
Request:
  • empty payload
Response:
  • available – Type: int, Range: [0 to 15]

Returns a bitmask of ports that are available for grouping. For example the value 5 or 0b0101 means: Port A and port C are connected to Bricklets that can be grouped together.

request/industrial_digital_in_4_bricklet/<UID>/set_edge_count_config
Request:
  • selection_mask – Type: int, Range: [0 to 216 - 1]
  • edge_type – Type: int, Range: See symbols, Default: 0
  • debounce – Type: int, Unit: 1 ms, Range: [0 to 255], Default: 100
Response:
  • no response

Configures the edge counter for the selected pins. A bitmask of 9 or 0b1001 will enable the edge counter for pins 0 and 3.

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
  • 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.

The edge counters use the grouping as set by request/industrial_digital_in_4_bricklet/<UID>/set_group.

The following symbols are available for this function:

For edge_type:

  • "rising" = 0
  • "falling" = 1
  • "both" = 2

New in version 2.0.1 (Plugin).

request/industrial_digital_in_4_bricklet/<UID>/get_edge_count_config
Request:
  • pin – Type: int, Range: [0 to 255]
Response:
  • edge_type – Type: int, Range: See symbols, Default: 0
  • debounce – Type: int, Unit: 1 ms, Range: [0 to 255], Default: 100

Returns the edge type and debounce time for the selected pin as set by request/industrial_digital_in_4_bricklet/<UID>/set_edge_count_config.

The following symbols are available for this function:

For edge_type:

  • "rising" = 0
  • "falling" = 1
  • "both" = 2

New in version 2.0.1 (Plugin).

request/industrial_digital_in_4_bricklet/<UID>/get_identity
Request:
  • empty payload
Response:
  • uid – Type: string, Length: up to 8
  • connected_uid – Type: string, Length: up to 8
  • position – Type: char, Range: ["a" to "h", "z"]
  • hardware_version – Type: [int, ...], Length: 3
    • 0: major – Type: int, Range: [0 to 255]
    • 1: minor – Type: int, Range: [0 to 255]
    • 2: revision – Type: int, Range: [0 to 255]
  • firmware_version – Type: [int, ...], Length: 3
    • 0: major – Type: int, Range: [0 to 255]
    • 1: minor – Type: int, Range: [0 to 255]
    • 2: revision – Type: int, Range: [0 to 255]
  • device_identifier – Type: int, Range: [0 to 216 - 1]
  • _display_name – Type: string

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 as position 'z'.

The device identifier numbers can be found here. If symbolic output is not disabled, the device identifier is mapped to the corresponding name in the format used in topics.

The display name contains the Industrial Digital In 4's name in a human readable form.

Callback Configuration Functions

request/industrial_digital_in_4_bricklet/<UID>/set_debounce_period
Request:
  • debounce – Type: int, Unit: 1 ms, Range: [0 to 232 - 1], Default: 100
Response:
  • no response

Sets the debounce period of the register/industrial_digital_in_4_bricklet/<UID>/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 Digital In 4 Bricklet, such as a button.

request/industrial_digital_in_4_bricklet/<UID>/get_debounce_period
Request:
  • empty payload
Response:
  • debounce – Type: int, Unit: 1 ms, Range: [0 to 232 - 1], Default: 100

Returns the debounce period as set by request/industrial_digital_in_4_bricklet/<UID>/set_debounce_period.

request/industrial_digital_in_4_bricklet/<UID>/set_interrupt
Request:
  • interrupt_mask – Type: int, Range: [0 to 216 - 1]
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 9 or 0b1001 will enable the interrupt for pins 0 and 3.

The interrupts use the grouping as set by request/industrial_digital_in_4_bricklet/<UID>/set_group.

The interrupt is delivered with the register/industrial_digital_in_4_bricklet/<UID>/interrupt callback.

request/industrial_digital_in_4_bricklet/<UID>/get_interrupt
Request:
  • empty payload
Response:
  • interrupt_mask – Type: int, Range: [0 to 216 - 1]

Returns the interrupt bitmask as set by request/industrial_digital_in_4_bricklet/<UID>/set_interrupt.

Callbacks

Callbacks can be registered to receive time critical or recurring data from the device. The registration is done with the corresponding .../register/... topic and an optional suffix. This suffix can be used to deregister the callback later.

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.

register/industrial_digital_in_4_bricklet/<UID>/interrupt
Register Request:
  • register – Type: bool
Callback Response:
  • interrupt_mask – Type: int, Range: [0 to 216 - 1]
  • value_mask – Type: int, Range: [0 to 216 - 1]

A callback can be registered for this event by publishing to the .../register/industrial_digital_in_4_bricklet/<UID>/interrupt[/<SUFFIX>] topic with the payload "true". An added callback can be removed by publishing to the same topic with the payload "false". To support multiple (de)registrations, e.g. for message filtering, an optional suffix can be used.

If the callback is triggered, a message with it's payload is published under the corresponding .../callback/industrial_digital_in_4_bricklet/<UID>/interrupt[/<SUFFIX>] topic for each registered suffix.

This callback is triggered whenever a change of the voltage level is detected on pins where the interrupt was activated with request/industrial_digital_in_4_bricklet/<UID>/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.

The interrupts use the grouping as set by request/industrial_digital_in_4_bricklet/<UID>/set_group.