Modbus - Voltage/Current Bricklet

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

API

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

Basic Functions

BrickletVoltageCurrent.get_current
Function ID:

1

Request:

empty payload

Response:
  • current -- int32

Returns the current. The value is in mA and between -20000mA and 20000mA.

If you want to get the current periodically, it is recommended to use the CALLBACK_CURRENT callback and set the period with set_current_callback_period.

BrickletVoltageCurrent.get_voltage
Function ID:

2

Request:

empty payload

Response:
  • voltage -- int32

Returns the voltage. The value is in mV and between 0mV and 36000mV.

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.

BrickletVoltageCurrent.get_power
Function ID:

3

Request:

empty payload

Response:
  • power -- int32

Returns the power. The value is in mW and between 0mV and 720000mW.

If you want to get the power periodically, it is recommended to use the CALLBACK_POWER callback and set the period with set_power_callback_period.

BrickletVoltageCurrent.set_configuration
Function ID:

4

Request:
  • averaging -- uint8
  • voltage_conversion_time -- uint8
  • current_conversion_time -- uint8
Response:

no response

Sets the configuration of the Voltage/Current Bricklet. It is possible to configure number of averages as well as voltage and current conversion time.

Averaging:

Value Number of Averages
0 1
1 4
2 16
3 64
4 128
5 256
6 512
>=7 1024

Voltage/Current conversion:

Value Conversion time
0 140µs
1 204µs
2 332µs
3 588µs
4 1.1ms
5 2.116ms
6 4.156ms
>=7 8.244ms

The default values are 3, 4 and 4 (64, 1.1ms, 1.1ms) for averaging, voltage conversion and current conversion.

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

  • 0: 1, for averaging
  • 1: 4, for averaging
  • 2: 16, for averaging
  • 3: 64, for averaging
  • 4: 128, for averaging
  • 5: 256, for averaging
  • 6: 512, for averaging
  • 7: 1024, for averaging
BrickletVoltageCurrent.get_configuration
Function ID:

5

Request:

empty payload

Response:
  • averaging -- uint8
  • voltage_conversion_time -- uint8
  • current_conversion_time -- uint8

Returns the configuration as set by set_configuration.

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

  • 0: 1, for averaging
  • 1: 4, for averaging
  • 2: 16, for averaging
  • 3: 64, for averaging
  • 4: 128, for averaging
  • 5: 256, for averaging
  • 6: 512, for averaging
  • 7: 1024, for averaging

Advanced Functions

BrickletVoltageCurrent.set_calibration
Function ID:

6

Request:
  • gain_multiplier -- uint16
  • gain_divisor -- uint16
Response:

no response

Since the shunt resistor that is used to measure the current is not perfectly precise, it needs to be calibrated by a multiplier and divisor if a very precise reading is needed.

For example, if you are expecting a measurement of 1000mA and you are measuring 1023mA, you can calibrate the Voltage/Current Bricklet by setting the multiplier to 1000 and the divisor to 1023.

BrickletVoltageCurrent.get_calibration
Function ID:

7

Request:

empty payload

Response:
  • gain_multiplier -- uint16
  • gain_divisor -- uint16

Returns the calibration as set by set_calibration.

BrickletVoltageCurrent.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

BrickletVoltageCurrent.set_current_callback_period
Function ID:

8

Request:
  • period -- uint32
Response:

no response

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

The CALLBACK_CURRENT callback is only triggered if the current has changed since the last triggering.

The default value is 0.

BrickletVoltageCurrent.get_current_callback_period
Function ID:

9

Request:

empty payload

Response:
  • period -- uint32

Returns the period as set by set_current_callback_period.

BrickletVoltageCurrent.set_voltage_callback_period
Function ID:

10

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.

BrickletVoltageCurrent.get_voltage_callback_period
Function ID:

11

Request:

empty payload

Response:
  • period -- uint32

Returns the period as set by set_voltage_callback_period.

BrickletVoltageCurrent.set_power_callback_period
Function ID:

12

Request:
  • period -- uint32
Response:

no response

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

The CALLBACK_POWER callback is only triggered if the power has changed since the last triggering.

The default value is 0.

BrickletVoltageCurrent.get_power_callback_period
Function ID:

13

Request:

empty payload

Response:
  • period -- uint32

Returns the period as set by get_power_callback_period.

BrickletVoltageCurrent.set_current_callback_threshold
Function ID:

14

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

no response

Sets the thresholds for the CALLBACK_CURRENT_REACHED callback.

The following options are possible:

Option Description
'x' Callback is turned off
'o' Callback is triggered when the current is outside the min and max values
'i' Callback is triggered when the current is inside the min and max values
'<' Callback is triggered when the current is smaller than the min value (max is ignored)
'>' Callback is triggered when the current 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
BrickletVoltageCurrent.get_current_callback_threshold
Function ID:

15

Request:

empty payload

Response:
  • option -- char
  • min -- int32
  • max -- int32

Returns the threshold as set by set_current_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
BrickletVoltageCurrent.set_voltage_callback_threshold
Function ID:

16

Request:
  • option -- char
  • min -- int32
  • max -- int32
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
BrickletVoltageCurrent.get_voltage_callback_threshold
Function ID:

17

Request:

empty payload

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
BrickletVoltageCurrent.set_power_callback_threshold
Function ID:

18

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

no response

Sets the thresholds for the CALLBACK_POWER_REACHED callback.

The following options are possible:

Option Description
'x' Callback is turned off
'o' Callback is triggered when the power is outside the min and max values
'i' Callback is triggered when the power is inside the min and max values
'<' Callback is triggered when the power is smaller than the min value (max is ignored)
'>' Callback is triggered when the power 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
BrickletVoltageCurrent.get_power_callback_threshold
Function ID:

19

Request:

empty payload

Response:
  • option -- char
  • min -- int32
  • max -- int32

Returns the threshold as set by set_power_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
BrickletVoltageCurrent.set_debounce_period
Function ID:

20

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.

BrickletVoltageCurrent.get_debounce_period
Function ID:

21

Request:

empty payload

Response:
  • debounce -- uint32

Returns the debounce period as set by set_debounce_period.

Callbacks

BrickletVoltageCurrent.CALLBACK_CURRENT
Function ID:

22

Response:
  • current -- int32

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

The CALLBACK_CURRENT callback is only triggered if the current has changed since the last triggering.

BrickletVoltageCurrent.CALLBACK_VOLTAGE
Function ID:

23

Response:
  • 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 sensor.

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

BrickletVoltageCurrent.CALLBACK_POWER
Function ID:

24

Response:
  • power -- int32

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

The CALLBACK_POWER callback is only triggered if the power has changed since the last triggering.

BrickletVoltageCurrent.CALLBACK_CURRENT_REACHED
Function ID:

25

Response:
  • current -- int32

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

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

BrickletVoltageCurrent.CALLBACK_VOLTAGE_REACHED
Function ID:

26

Response:
  • 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 sensor.

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

BrickletVoltageCurrent.CALLBACK_POWER_REACHED
Function ID:

27

Response:
  • power -- int32

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

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