MQTT - Industrial Digital Out 4 Bricklet 2.0

This is the description of the MQTT API bindings for the Industrial Digital Out 4 Bricklet 2.0. General information and technical specifications for the Industrial Digital Out 4 Bricklet 2.0 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 Out 4 Bricklet 2.0

setup:
    # Set channels alternating high/low 10 times with 100 ms delay
    for i in 0 1 2 3 4 5 6 7 8 9; do
    
        wait for 0.1s 
    
        publish '{"value": [true,false,false,false]}' to tinkerforge/request/industrial_digital_out_4_v2_bricklet/XYZ/set_value 
    
        wait for 0.1s 
    
        publish '{"value": [false,true,false,false]}' to tinkerforge/request/industrial_digital_out_4_v2_bricklet/XYZ/set_value 
    
        wait for 0.1s 
    
        publish '{"value": [false,false,true,false]}' to tinkerforge/request/industrial_digital_out_4_v2_bricklet/XYZ/set_value 
    
        wait for 0.1s 
    
        publish '{"value": [false,false,false,true]}' to tinkerforge/request/industrial_digital_out_4_v2_bricklet/XYZ/set_value 
    
    done

API

All published payload to an from the MQTT bindings is in the JSON format.

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

Basic Functions

request/industrial_digital_out_4_v2_bricklet/<UID>/set_value
Request payload:
 
  • value -- [bool,bool,bool,bool]

Sets the output value of all four channels. A value of true or false outputs logic 1 or logic 0 respectively on the corresponding channel.

Use request/industrial_digital_out_4_v2_bricklet/<UID>/set_selected_value to change only one output channel state.

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

For example: (True, True, False, False) will turn the channels 0-1 high and the channels 2-3 low.

request/industrial_digital_out_4_v2_bricklet/<UID>/get_value
Response payload:
 
  • value -- [bool,bool,bool,bool]

Returns the logic levels that are currently output on the channels.

request/industrial_digital_out_4_v2_bricklet/<UID>/set_selected_value
Request payload:
 
  • channel -- int
  • value -- bool

Sets the output value of a specific channel without affecting the other channels.

A running monoflop timer or PWM for the specified channel will be aborted if this function is called.

request/industrial_digital_out_4_v2_bricklet/<UID>/set_channel_led_config
Request payload:
 
  • channel -- int
  • config -- int (has symbols)

Each channel has a corresponding LED. You can turn the LED off, on or show a heartbeat. You can also set the LED to "Channel Status". In this mode the LED is on if the channel is high and off otherwise.

By default all channel LEDs are configured as "Channel Status".

The following symbols are available for this function:

for config:

  • "Off" = 0
  • "On" = 1
  • "ShowHeartbeat" = 2
  • "ShowChannelStatus" = 3
request/industrial_digital_out_4_v2_bricklet/<UID>/get_channel_led_config
Request payload:
 
  • channel -- int
Response payload:
 
  • config -- int (has symbols)

Returns the channel LED configuration as set by request/industrial_digital_out_4_v2_bricklet/<UID>/set_channel_led_config

The following symbols are available for this function:

for config:

  • "Off" = 0
  • "On" = 1
  • "ShowHeartbeat" = 2
  • "ShowChannelStatus" = 3

Advanced Functions

request/industrial_digital_out_4_v2_bricklet/<UID>/set_monoflop
Request payload:
 
  • channel -- int
  • value -- bool
  • time -- int

The first parameter is the desired state of the channel (true means output high and false means output low). The second parameter indicates the time (in ms) that the channel should hold the state.

If this function is called with the parameters (true, 1500): The channel will turn on and in 1.5s it will turn off again.

A PWM for the selected channel will be aborted if this function is called.

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

request/industrial_digital_out_4_v2_bricklet/<UID>/get_monoflop
Request payload:
 
  • channel -- int
Response payload:
 
  • value -- bool
  • time -- int
  • time_remaining -- int

Returns (for the given channel) the current value and the time as set by request/industrial_digital_out_4_v2_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_digital_out_4_v2_bricklet/<UID>/set_pwm_configuration
Request payload:
 
  • channel -- int
  • frequency -- int
  • duty_cycle -- int

Activates a PWM for the given channel with the frequency given in 1/10Hz and the duty cycle given in 1/100%.

To turn the PWM off again, you can set the frequency to 0 or any other function that changes a value of the channel (e.g. request/industrial_digital_out_4_v2_bricklet/<UID>/set_selected_value).

The maximum duty cycle value is 10000 (100%). The optocoupler of the Industrial Digital Out 4 Bricklet 2.0 has a rise time and fall time of 11.5us (each) at 24V. So the maximum useful frequency value is about 400000 (40kHz).

A running monoflop timer for the given channel will be aborted if this function is called.

The default values are 0, 0.

request/industrial_digital_out_4_v2_bricklet/<UID>/get_pwm_configuration
Request payload:
 
  • channel -- int
Response payload:
 
  • frequency -- int
  • duty_cycle -- int

Returns the PWM configuration as set by request/industrial_digital_out_4_v2_bricklet/<UID>/set_pwm_configuration.

request/industrial_digital_out_4_v2_bricklet/<UID>/get_spitfp_error_count
Response payload:
 
  • error_count_ack_checksum -- int
  • error_count_message_checksum -- int
  • error_count_frame -- int
  • error_count_overflow -- int

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.

request/industrial_digital_out_4_v2_bricklet/<UID>/set_bootloader_mode
Request payload:
 
  • mode -- int (has symbols)
Response payload:
 
  • status -- int (has symbols)

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 symbols are available for this function:

for mode:

  • "Bootloader" = 0
  • "Firmware" = 1
  • "BootloaderWaitForReboot" = 2
  • "FirmwareWaitForReboot" = 3
  • "FirmwareWaitForEraseAndReboot" = 4

for status:

  • "OK" = 0
  • "InvalidMode" = 1
  • "NoChange" = 2
  • "EntryFunctionNotPresent" = 3
  • "DeviceIdentifierIncorrect" = 4
  • "CRCMismatch" = 5
request/industrial_digital_out_4_v2_bricklet/<UID>/get_bootloader_mode
Response payload:
 
  • mode -- int (has symbols)

Returns the current bootloader mode, see request/industrial_digital_out_4_v2_bricklet/<UID>/set_bootloader_mode.

The following symbols are available for this function:

for mode:

  • "Bootloader" = 0
  • "Firmware" = 1
  • "BootloaderWaitForReboot" = 2
  • "FirmwareWaitForReboot" = 3
  • "FirmwareWaitForEraseAndReboot" = 4
request/industrial_digital_out_4_v2_bricklet/<UID>/set_write_firmware_pointer
Request payload:
 
  • pointer -- int

Sets the firmware pointer for request/industrial_digital_out_4_v2_bricklet/<UID>/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.

request/industrial_digital_out_4_v2_bricklet/<UID>/write_firmware
Request payload:
 
  • data -- [int,... (x64)]
Response payload:
 
  • status -- int

Writes 64 Bytes of firmware at the position as written by request/industrial_digital_out_4_v2_bricklet/<UID>/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.

request/industrial_digital_out_4_v2_bricklet/<UID>/set_status_led_config
Request payload:
 
  • config -- int (has symbols)

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 symbols are available for this function:

for config:

  • "Off" = 0
  • "On" = 1
  • "ShowHeartbeat" = 2
  • "ShowStatus" = 3
request/industrial_digital_out_4_v2_bricklet/<UID>/get_status_led_config
Response payload:
 
  • config -- int (has symbols)

Returns the configuration as set by request/industrial_digital_out_4_v2_bricklet/<UID>/set_status_led_config

The following symbols are available for this function:

for config:

  • "Off" = 0
  • "On" = 1
  • "ShowHeartbeat" = 2
  • "ShowStatus" = 3
request/industrial_digital_out_4_v2_bricklet/<UID>/get_chip_temperature
Response payload:
 
  • temperature -- int

Returns the temperature in °C 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.

request/industrial_digital_out_4_v2_bricklet/<UID>/reset

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!

request/industrial_digital_out_4_v2_bricklet/<UID>/write_uid
Request payload:
 
  • uid -- int

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.

request/industrial_digital_out_4_v2_bricklet/<UID>/read_uid
Response payload:
 
  • uid -- int

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

request/industrial_digital_out_4_v2_bricklet/<UID>/get_identity
Response payload:
 
  • uid -- string
  • connected_uid -- string
  • position -- string
  • hardware_version -- [int,int,int]
  • firmware_version -- [int,int,int]
  • device_identifier -- int (has symbols)
  • _display_name -- 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' or 'd'.

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 Out 4 2.0'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_digital_out_4_v2_bricklet/<UID>/monoflop_done
Request payload:
 
  • register -- bool
Response payload:
 
  • channel -- int
  • value -- bool

A callback can be registered for this event by publishing to the .../register/industrial_digital_out_4_v2_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_digital_out_4_v2_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 channel and the current value of the channel (the value after the monoflop).