Modbus - Industrial Dual Analog In Bricklet

This is the description of the Modbus protocol 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.

API

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

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

BrickletIndustrialDualAnalogIn.get_voltage
Function ID:

1

Request:
  • channel -- uint8
Response:
  • voltage -- int32

Returns the voltage for the given channel in mV.

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.

Advanced Functions

BrickletIndustrialDualAnalogIn.set_sample_rate
Function ID:

8

Request:
  • rate -- uint8
Response:

no response

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 meanings are defined for the parameters of this function:

  • 0: 976 sps, for rate
  • 1: 488 sps, for rate
  • 2: 244 sps, for rate
  • 3: 122 sps, for rate
  • 4: 61 sps, for rate
  • 5: 4 sps, for rate
  • 6: 2 sps, for rate
  • 7: 1 sps, for rate
BrickletIndustrialDualAnalogIn.get_sample_rate
Function ID:

9

Request:

empty payload

Response:
  • rate -- uint8

Returns the sample rate as set by set_sample_rate.

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

  • 0: 976 sps, for rate
  • 1: 488 sps, for rate
  • 2: 244 sps, for rate
  • 3: 122 sps, for rate
  • 4: 61 sps, for rate
  • 5: 4 sps, for rate
  • 6: 2 sps, for rate
  • 7: 1 sps, for rate
BrickletIndustrialDualAnalogIn.set_calibration
Function ID:

10

Request:
  • offset -- int32[2]
  • gain -- int32[2]
Response:

no response

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

BrickletIndustrialDualAnalogIn.get_calibration
Function ID:

11

Request:

empty payload

Response:
  • offset -- int32[2]
  • gain -- int32[2]

Returns the calibration as set by set_calibration.

BrickletIndustrialDualAnalogIn.get_adc_values
Function ID:

12

Request:

empty payload

Response:
  • value -- int32[2]

Returns the ADC values as given by the MCP3911 IC. This function is needed for proper calibration, see set_calibration.

BrickletIndustrialDualAnalogIn.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

BrickletIndustrialDualAnalogIn.set_voltage_callback_period
Function ID:

2

Request:
  • channel -- uint8
  • period -- uint32
Response:

no response

Sets the period in ms with which the CALLBACK_VOLTAGE callback is triggered periodically for the given channel. 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.

BrickletIndustrialDualAnalogIn.get_voltage_callback_period
Function ID:

3

Request:
  • channel -- uint8
Response:
  • period -- uint32

Returns the period as set by set_voltage_callback_period.

BrickletIndustrialDualAnalogIn.set_voltage_callback_threshold
Function ID:

4

Request:
  • channel -- uint8
  • option -- char
  • min -- int32
  • max -- int32
Response:

no response

Sets the thresholds for the CALLBACK_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 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
BrickletIndustrialDualAnalogIn.get_voltage_callback_threshold
Function ID:

5

Request:
  • channel -- uint8
Response:
  • option -- char
  • min -- int32
  • max -- int32

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
BrickletIndustrialDualAnalogIn.set_debounce_period
Function ID:

6

Request:
  • debounce -- uint32
Response:

no response

Sets the period in ms with which the threshold callback

is triggered, if the threshold

keeps being reached.

The default value is 100.

BrickletIndustrialDualAnalogIn.get_debounce_period
Function ID:

7

Request:

empty payload

Response:
  • debounce -- uint32

Returns the debounce period as set by set_debounce_period.

Callbacks

BrickletIndustrialDualAnalogIn.CALLBACK_VOLTAGE
Function ID:

13

Response:
  • channel -- uint8
  • voltage -- int32

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

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

BrickletIndustrialDualAnalogIn.CALLBACK_VOLTAGE_REACHED
Function ID:

14

Response:
  • channel -- uint8
  • voltage -- int32

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

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