MQTT - Industrial Quad Relay Bricklet

This is the description of the MQTT API bindings for the Industrial Quad Relay Bricklet. General information and technical specifications for the Industrial Quad Relay 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 Quad Relay Bricklet

setup:
    # Turn relays alternating on/off 10 times with 100 ms delay
    for i in 0..9

        wait for 0.1s

        publish '{"value_mask": 1}' to tinkerforge/request/industrial_quad_relay_bricklet/XYZ/set_value # 1 << 0 = 1

        wait for 0.1s

        publish '{"value_mask": 2}' to tinkerforge/request/industrial_quad_relay_bricklet/XYZ/set_value # 1 << 1 = 2

        wait for 0.1s

        publish '{"value_mask": 4}' to tinkerforge/request/industrial_quad_relay_bricklet/XYZ/set_value # 1 << 2 = 4

        wait for 0.1s

        publish '{"value_mask": 8}' to tinkerforge/request/industrial_quad_relay_bricklet/XYZ/set_value # 1 << 3 = 8

    endfor

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_quad_relay_bricklet/<UID>/set_value
Request:
  • value_mask – Type: int, Range: [0 to 216 - 1]
Response:
  • no response

Sets the output value with a bitmask (16bit). A 1 in the bitmask means relay closed and a 0 means relay open.

For example: The value 3 or 0b0011 will close the relay of pins 0-1 and open the other pins.

If no groups are used (see request/industrial_quad_relay_bricklet/<UID>/set_group), the pins correspond to the markings on the Industrial Quad Relay 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.

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

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

Returns the bitmask as set by request/industrial_quad_relay_bricklet/<UID>/set_value.

Advanced Functions

request/industrial_quad_relay_bricklet/<UID>/set_monoflop
Request:
  • selection_mask – Type: int, Range: [0 to 216 - 1]
  • value_mask – Type: int, Range: [0 to 216 - 1]
  • time – Type: int, Unit: 1 ms, Range: [0 to 232 - 1]
Response:
  • no response

Configures a monoflop of the pins specified by the first parameter bitmask.

The second parameter is a bitmask with the desired value of the specified pins. A 1 in the bitmask means relay closed and a 0 means relay open.

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 close and pin 3 will open. In 1.5s pin 0 will open and pin 3 will close again.

A monoflop can be used as a fail-safe mechanism. For example: Lets assume you have a RS485 bus and a Quad Relay 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 closed. Pin 0 will be closed all the time. If now the RS485 connection is lost, then pin 0 will be opened in at most two seconds.

request/industrial_quad_relay_bricklet/<UID>/get_monoflop
Request:
  • pin – Type: int, Range: [0 to 15]
Response:
  • value – Type: int, Range: [0 to 1]
  • time – Type: int, Unit: 1 ms, Range: [0 to 232 - 1]
  • time_remaining – Type: int, Unit: 1 ms, Range: [0 to 232 - 1]

Returns (for the given pin) the current value and the time as set by request/industrial_quad_relay_bricklet/<UID>/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.

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

Sets a group of Quad Relay Bricklets that should work together. You can find Bricklets that can be grouped together with request/industrial_quad_relay_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 Quad Relay Bricklets connected to port A and port B respectively, you could call with ['a', 'b', 'n', 'n'].

Now the pins on the Quad Relay on port A are assigned to 0-3 and the pins on the Quad Relay on port B are assigned to 4-7. It is now possible to call request/industrial_quad_relay_bricklet/<UID>/set_value and control two Bricklets at the same time.

request/industrial_quad_relay_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_quad_relay_bricklet/<UID>/set_group

request/industrial_quad_relay_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_quad_relay_bricklet/<UID>/set_selected_values
Request:
  • selection_mask – Type: int, Range: [0 to 216 - 1]
  • value_mask – Type: int, Range: [0 to 216 - 1]
Response:
  • no response

Sets the output value with a bitmask, according to the selection mask. The bitmask is 16 bit long, true refers to a closed relay and false refers to an open relay.

For example: The values (3, 1) or (0b0011, 0b0001) will close the relay of pin 0, open the relay of pin 1 and leave the others untouched.

If no groups are used (see request/industrial_quad_relay_bricklet/<UID>/set_group), the pins correspond to the markings on the Industrial Quad Relay 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.

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

request/industrial_quad_relay_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", "i", "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). The Raspberry Pi HAT (Zero) Brick is always at position 'i' and the 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 Quad Relay's name in a human readable form.

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_quad_relay_bricklet/<UID>/monoflop_done
Register Request:
  • register – Type: bool
Callback Response:
  • selection_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_quad_relay_bricklet/<UID>/monoflop_done[/<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_quad_relay_bricklet/<UID>/monoflop_done[/<SUFFIX>] topic for each registered suffix.

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