Modbus - Analog In Bricklet

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

API

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

Basic Functions

BrickletAnalogIn.get_voltage
Function ID:

1

Request:

empty payload

Response:
  • voltage -- uint16

Returns the voltage of the sensor. The value is in mV and between 0V and 45V. The resolution between 0 and 6V is about 2mV. Between 6 and 45V the resolution is about 10mV.

If you want to get the voltage periodically, it is recommended to use the CALLBACK_VOLTAGE callback and set the period with set_voltage_callback_period.

BrickletAnalogIn.set_range
Function ID:

17

Request:
  • range -- uint8
Response:

no response

Sets the measurement range. Possible ranges:

  • 0: Automatically switched
  • 1: 0V - 6.05V, ~1.48mV resolution
  • 2: 0V - 10.32V, ~2.52mV resolution
  • 3: 0V - 36.30V, ~8.86mV resolution
  • 4: 0V - 45.00V, ~11.25mV resolution
  • 5: 0V - 3.3V, ~0.81mV resolution, new in version 2.0.3 (Plugin)

The default measurement range is 0.

New in version 2.0.1 (Plugin).

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

  • 0: automatic, for range
  • 1: up to 6v, for range
  • 2: up to 10v, for range
  • 3: up to 36v, for range
  • 4: up to 45v, for range
  • 5: up to 3v, for range
BrickletAnalogIn.get_range
Function ID:

18

Request:

empty payload

Response:
  • range -- uint8

Returns the measurement range as set by set_range.

New in version 2.0.1 (Plugin).

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

  • 0: automatic, for range
  • 1: up to 6v, for range
  • 2: up to 10v, for range
  • 3: up to 36v, for range
  • 4: up to 45v, for range
  • 5: up to 3v, for range

Advanced Functions

BrickletAnalogIn.get_analog_value
Function ID:

2

Request:

empty payload

Response:
  • value -- uint16

Returns the value as read by a 12-bit analog-to-digital converter. The value is between 0 and 4095.

Note

The value returned by get_voltage is averaged over several samples to yield less noise, while get_analog_value gives back raw unfiltered analog values. The only reason to use get_analog_value is, if you need the full resolution of the analog-to-digital converter.

If you want the analog value periodically, it is recommended to use the CALLBACK_ANALOG_VALUE callback and set the period with set_analog_value_callback_period.

BrickletAnalogIn.set_averaging
Function ID:

19

Request:
  • average -- uint8
Response:

no response

Set the length of a averaging for the voltage value.

Setting the length to 0 will turn the averaging completely off. If the averaging is off, there is more noise on the data, but the data is without delay.

The default value is 50.

New in version 2.0.3 (Plugin).

BrickletAnalogIn.get_averaging
Function ID:

20

Request:

empty payload

Response:
  • average -- uint8

Returns the averaging configuration as set by set_averaging.

New in version 2.0.3 (Plugin).

BrickletAnalogIn.get_identity
Function ID:

255

Request:

empty payload

Response:
  • uid -- char[8]
  • connected_uid -- char[8]
  • position -- char
  • hardware_version -- uint8[3]
  • firmware_version -- uint8[3]
  • device_identifier -- uint16

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

Callback Configuration Functions

BrickletAnalogIn.set_voltage_callback_period
Function ID:

3

Request:
  • period -- uint32
Response:

no response

Sets the period in ms with which the CALLBACK_VOLTAGE callback is triggered periodically. A value of 0 turns the callback off.

The CALLBACK_VOLTAGE callback is only triggered if the voltage has changed since the last triggering.

The default value is 0.

BrickletAnalogIn.get_voltage_callback_period
Function ID:

4

Request:

empty payload

Response:
  • period -- uint32

Returns the period as set by set_voltage_callback_period.

BrickletAnalogIn.set_analog_value_callback_period
Function ID:

5

Request:
  • period -- uint32
Response:

no response

Sets the period in ms with which the CALLBACK_ANALOG_VALUE callback is triggered periodically. A value of 0 turns the callback off.

The CALLBACK_ANALOG_VALUE callback is only triggered if the analog value has changed since the last triggering.

The default value is 0.

BrickletAnalogIn.get_analog_value_callback_period
Function ID:

6

Request:

empty payload

Response:
  • period -- uint32

Returns the period as set by set_analog_value_callback_period.

BrickletAnalogIn.set_voltage_callback_threshold
Function ID:

7

Request:
  • option -- char
  • min -- uint16
  • max -- uint16
Response:

no response

Sets the thresholds for the CALLBACK_VOLTAGE_REACHED callback.

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 meanings are defined for the parameters of this function:

  • x: off, for option
  • o: outside, for option
  • i: inside, for option
  • <: smaller, for option
  • >: greater, for option
BrickletAnalogIn.get_voltage_callback_threshold
Function ID:

8

Request:

empty payload

Response:
  • option -- char
  • min -- uint16
  • max -- uint16

Returns the threshold as set by set_voltage_callback_threshold.

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

  • x: off, for option
  • o: outside, for option
  • i: inside, for option
  • <: smaller, for option
  • >: greater, for option
BrickletAnalogIn.set_analog_value_callback_threshold
Function ID:

9

Request:
  • option -- char
  • min -- uint16
  • max -- uint16
Response:

no response

Sets the thresholds for the CALLBACK_ANALOG_VALUE_REACHED callback.

The following options are possible:

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

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

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

  • x: off, for option
  • o: outside, for option
  • i: inside, for option
  • <: smaller, for option
  • >: greater, for option
BrickletAnalogIn.get_analog_value_callback_threshold
Function ID:

10

Request:

empty payload

Response:
  • option -- char
  • min -- uint16
  • max -- uint16

Returns the threshold as set by set_analog_value_callback_threshold.

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

  • x: off, for option
  • o: outside, for option
  • i: inside, for option
  • <: smaller, for option
  • >: greater, for option
BrickletAnalogIn.set_debounce_period
Function ID:

11

Request:
  • debounce -- uint32
Response:

no response

Sets the period in ms with which the threshold callbacks

are triggered, if the thresholds

keep being reached.

The default value is 100.

BrickletAnalogIn.get_debounce_period
Function ID:

12

Request:

empty payload

Response:
  • debounce -- uint32

Returns the debounce period as set by set_debounce_period.

Callbacks

BrickletAnalogIn.CALLBACK_VOLTAGE
Function ID:

13

Response:
  • voltage -- uint16

This callback is triggered periodically with the period that is set by set_voltage_callback_period. The response value is the voltage of the sensor.

The CALLBACK_VOLTAGE callback is only triggered if the voltage has changed since the last triggering.

BrickletAnalogIn.CALLBACK_ANALOG_VALUE
Function ID:

14

Response:
  • value -- uint16

This callback is triggered periodically with the period that is set by set_analog_value_callback_period. The response value is the analog value of the sensor.

The CALLBACK_ANALOG_VALUE callback is only triggered if the voltage has changed since the last triggering.

BrickletAnalogIn.CALLBACK_VOLTAGE_REACHED
Function ID:

15

Response:
  • voltage -- uint16

This callback is triggered when the threshold as set by set_voltage_callback_threshold is reached. The response value is the voltage of the sensor.

If the threshold keeps being reached, the callback is triggered periodically with the period as set by set_debounce_period.

BrickletAnalogIn.CALLBACK_ANALOG_VALUE_REACHED
Function ID:

16

Response:
  • value -- uint16

This callback is triggered when the threshold as set by set_analog_value_callback_threshold is reached. The response value is the analog value of the sensor.

If the threshold keeps being reached, the callback is triggered periodically with the period as set by set_debounce_period.