MQTT - Industrial Dual Analog In Bricklet

This is the description of the MQTT API bindings for the Industrial Dual Analog In Bricklet. General information and technical specifications for the Industrial Dual Analog In 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 Dual Analog In Bricklet

setup:
    # Get current voltage from channel 1
    subscribe to tinkerforge/response/industrial_dual_analog_in_bricklet/XYZ/get_voltage
    publish '{"channel": 1}' to tinkerforge/request/industrial_dual_analog_in_bricklet/XYZ/get_voltage

Callback

Download (example-callback.txt)

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# Change XYZ to the UID of your Industrial Dual Analog In Bricklet

setup:
    # Handle incoming voltage callbacks
    subscribe to tinkerforge/callback/industrial_dual_analog_in_bricklet/XYZ/voltage
    publish '{"register": true}' to tinkerforge/register/industrial_dual_analog_in_bricklet/XYZ/voltage # Register voltage callback
    
    # Set period for voltage (channel 1) callback to 1s (1000ms)
    # Note: The voltage (channel 1) callback is only called every second
    #       if the voltage (channel 1) has changed since the last call!
    publish '{"channel": 1, "period": 1000}' to tinkerforge/request/industrial_dual_analog_in_bricklet/XYZ/set_voltage_callback_period

Threshold

Download (example-threshold.txt)

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# Change XYZ to the UID of your Industrial Dual Analog In Bricklet

setup:
    # Get threshold callbacks with a debounce time of 10 seconds (10000ms)
    publish '{"debounce": 10000}' to tinkerforge/request/industrial-dual-analog-in_bricklet/XYZ/set_debounce_period
    
    # Handle incoming voltage reached callbacks
    subscribe to tinkerforge/callback/industrial_dual_analog_in_bricklet/XYZ/voltage_reached
    publish '{"register": true}' to tinkerforge/register/industrial_dual_analog_in_bricklet/XYZ/voltage_reached # Register voltage_reached callback
    
    # Configure threshold for voltage (channel 1) "greater than 10 V"
    publish '{"channel": 1, "option": "greater", "min": 10000, "max": 0}' to tinkerforge/request/industrial_dual_analog_in_bricklet/XYZ/set_voltage_callback_threshold

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 attribute "_ERROR". It is published on the corresponding response topic: .../response/... for .../request/... and .../callback/... for .../register/....

The Bricklet has two input channel. Functions that are related directly to a channel have a channel parameter to specify one of the two channels. Valid values for the channel parameter are 0 and 1.

Basic Functions

request/industrial_dual_analog_in_bricklet/<UID>/get_voltage
Request payload:
 
  • channel -- int
Response payload:
 
  • voltage -- int

Returns the voltage for the given channel in mV.

If you want to get the voltage periodically, it is recommended to use the register/industrial_dual_analog_in_bricklet/<UID>/voltage callback and set the period with request/industrial_dual_analog_in_bricklet/<UID>/set_voltage_callback_period.

Advanced Functions

request/industrial_dual_analog_in_bricklet/<UID>/set_sample_rate
Request payload:
 
  • rate -- int (has symbols)

Sets the sample rate. The sample rate can be between 1 sample per second and 976 samples per second. Decreasing the sample rate will also decrease the noise on the data.

The default value is 6 (2 samples per second).

The following symbols are available for this function:

for rate:

  • "976SPS" = 0
  • "488SPS" = 1
  • "244SPS" = 2
  • "122SPS" = 3
  • "61SPS" = 4
  • "4SPS" = 5
  • "2SPS" = 6
  • "1SPS" = 7
request/industrial_dual_analog_in_bricklet/<UID>/get_sample_rate
Response payload:
 
  • rate -- int (has symbols)

Returns the sample rate as set by request/industrial_dual_analog_in_bricklet/<UID>/set_sample_rate.

The following symbols are available for this function:

for rate:

  • "976SPS" = 0
  • "488SPS" = 1
  • "244SPS" = 2
  • "122SPS" = 3
  • "61SPS" = 4
  • "4SPS" = 5
  • "2SPS" = 6
  • "1SPS" = 7
request/industrial_dual_analog_in_bricklet/<UID>/set_calibration
Request payload:
 
  • offset -- [int,int]
  • gain -- [int,int]

Sets offset and gain of MCP3911 internal calibration registers.

See MCP3911 datasheet 7.7 and 7.8. The Industrial Dual Analog In Bricklet is already factory calibrated by Tinkerforge. It should not be necessary for you to use this function

request/industrial_dual_analog_in_bricklet/<UID>/get_calibration
Response payload:
 
  • offset -- [int,int]
  • gain -- [int,int]

Returns the calibration as set by request/industrial_dual_analog_in_bricklet/<UID>/set_calibration.

request/industrial_dual_analog_in_bricklet/<UID>/get_adc_values
Response payload:
 
  • value -- [int,int]

Returns the ADC values as given by the MCP3911 IC. This function is needed for proper calibration, see request/industrial_dual_analog_in_bricklet/<UID>/set_calibration.

request/industrial_dual_analog_in_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 Dual Analog In's name in a human readable form.

Callback Configuration Functions

request/industrial_dual_analog_in_bricklet/<UID>/set_voltage_callback_period
Request payload:
 
  • channel -- int
  • period -- int

Sets the period in ms with which the register/industrial_dual_analog_in_bricklet/<UID>/voltage callback is triggered periodically for the given channel. A value of 0 turns the callback off.

The register/industrial_dual_analog_in_bricklet/<UID>/voltage callback is only triggered if the voltage has changed since the last triggering.

The default value is 0.

request/industrial_dual_analog_in_bricklet/<UID>/get_voltage_callback_period
Request payload:
 
  • channel -- int
Response payload:
 
  • period -- int

Returns the period as set by request/industrial_dual_analog_in_bricklet/<UID>/set_voltage_callback_period.

request/industrial_dual_analog_in_bricklet/<UID>/set_voltage_callback_threshold
Request payload:
 
  • channel -- int
  • option -- string (has symbols)
  • min -- int
  • max -- int

Sets the thresholds for the register/industrial_dual_analog_in_bricklet/<UID>/voltage_reached callback for the given channel.

The following options are possible:

Option Description
'x' Callback is turned off
'o' Callback is triggered when the voltage is outside the min and max values
'i' Callback is triggered when the voltage is inside the min and max values
'<' Callback is triggered when the voltage is smaller than the min value (max is ignored)
'>' Callback is triggered when the voltage is greater than the min value (max is ignored)

The default value is ('x', 0, 0).

The following symbols are available for this function:

for option:

  • "Off" = 'x'
  • "Outside" = 'o'
  • "Inside" = 'i'
  • "Smaller" = '<'
  • "Greater" = '>'
request/industrial_dual_analog_in_bricklet/<UID>/get_voltage_callback_threshold
Request payload:
 
  • channel -- int
Response payload:
 
  • option -- string (has symbols)
  • min -- int
  • max -- int

Returns the threshold as set by request/industrial_dual_analog_in_bricklet/<UID>/set_voltage_callback_threshold.

The following symbols are available for this function:

for option:

  • "Off" = 'x'
  • "Outside" = 'o'
  • "Inside" = 'i'
  • "Smaller" = '<'
  • "Greater" = '>'
request/industrial_dual_analog_in_bricklet/<UID>/set_debounce_period
Request payload:
 
  • debounce -- int

Sets the period in ms with which the threshold callback

is triggered, if the threshold

keeps being reached.

The default value is 100.

request/industrial_dual_analog_in_bricklet/<UID>/get_debounce_period
Response payload:
 
  • debounce -- int

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

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_dual_analog_in_bricklet/<UID>/voltage
Request payload:
 
  • register -- bool
Response payload:
 
  • channel -- int
  • voltage -- int

A callback can be registered for this event by publishing to the .../register/industrial_dual_analog_in_bricklet/<UID>/voltage[/<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_dual_analog_in_bricklet/<UID>/voltage[/<SUFFIX>] topic for each registered suffix.

This callback is triggered periodically with the period that is set by request/industrial_dual_analog_in_bricklet/<UID>/set_voltage_callback_period. The callback payload is the voltage of the channel.

The register/industrial_dual_analog_in_bricklet/<UID>/voltage callback is only triggered if the voltage has changed since the last triggering.

register/industrial_dual_analog_in_bricklet/<UID>/voltage_reached
Request payload:
 
  • register -- bool
Response payload:
 
  • channel -- int
  • voltage -- int

A callback can be registered for this event by publishing to the .../register/industrial_dual_analog_in_bricklet/<UID>/voltage_reached[/<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_dual_analog_in_bricklet/<UID>/voltage_reached[/<SUFFIX>] topic for each registered suffix.

This callback is triggered when the threshold as set by request/industrial_dual_analog_in_bricklet/<UID>/set_voltage_callback_threshold is reached. The callback payload is the voltage of the channel.

If the threshold keeps being reached, the callback is triggered periodically with the period as set by request/industrial_dual_analog_in_bricklet/<UID>/set_debounce_period.