Modbus - Voltage/Current Bricklet 2.0

This is the description of the Modbus protocol for the Voltage/Current Bricklet 2.0. General information and technical specifications for the Voltage/Current Bricklet 2.0 are summarized in its hardware description.

API

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

Basic Functions

BrickletVoltageCurrentV2.get_current
Function ID:
  • 1
Request:
  • empty payload
Response:
  • current – Type: int32, Unit: 1 mA, Range: [-20000 to 20000]

Returns the current.

If you want to get the value periodically, it is recommended to use the CALLBACK_CURRENT callback. You can set the callback configuration with set_current_callback_configuration.

BrickletVoltageCurrentV2.get_voltage
Function ID:
  • 5
Request:
  • empty payload
Response:
  • voltage – Type: int32, Unit: 1 mV, Range: [0 to 36000]

Returns the voltage.

If you want to get the value periodically, it is recommended to use the CALLBACK_VOLTAGE callback. You can set the callback configuration with set_voltage_callback_configuration.

BrickletVoltageCurrentV2.get_power
Function ID:
  • 9
Request:
  • empty payload
Response:
  • power – Type: int32, Unit: 1 mW, Range: [0 to 720000]

Returns the power.

If you want to get the value periodically, it is recommended to use the CALLBACK_POWER callback. You can set the callback configuration with set_power_callback_configuration.

BrickletVoltageCurrentV2.set_configuration
Function ID:
  • 13
Request:
  • averaging – Type: uint8, Range: See meanings, Default: 3
  • voltage_conversion_time – Type: uint8, Range: See meanings, Default: 4
  • current_conversion_time – Type: uint8, Range: See meanings, Default: 4
Response:
  • no response

Sets the configuration of the Voltage/Current Bricklet 2.0. It is possible to configure number of averages as well as voltage and current conversion time.

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

For averaging:

  • 0 = 1
  • 1 = 4
  • 2 = 16
  • 3 = 64
  • 4 = 128
  • 5 = 256
  • 6 = 512
  • 7 = 1024

For voltage_conversion_time:

  • 0 = 140us
  • 1 = 204us
  • 2 = 332us
  • 3 = 588us
  • 4 = 1.1ms
  • 5 = 2.116ms
  • 6 = 4.156ms
  • 7 = 8.244ms

For current_conversion_time:

  • 0 = 140us
  • 1 = 204us
  • 2 = 332us
  • 3 = 588us
  • 4 = 1.1ms
  • 5 = 2.116ms
  • 6 = 4.156ms
  • 7 = 8.244ms
BrickletVoltageCurrentV2.get_configuration
Function ID:
  • 14
Request:
  • empty payload
Response:
  • averaging – Type: uint8, Range: See meanings, Default: 3
  • voltage_conversion_time – Type: uint8, Range: See meanings, Default: 4
  • current_conversion_time – Type: uint8, Range: See meanings, Default: 4

Returns the configuration as set by set_configuration.

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

For averaging:

  • 0 = 1
  • 1 = 4
  • 2 = 16
  • 3 = 64
  • 4 = 128
  • 5 = 256
  • 6 = 512
  • 7 = 1024

For voltage_conversion_time:

  • 0 = 140us
  • 1 = 204us
  • 2 = 332us
  • 3 = 588us
  • 4 = 1.1ms
  • 5 = 2.116ms
  • 6 = 4.156ms
  • 7 = 8.244ms

For current_conversion_time:

  • 0 = 140us
  • 1 = 204us
  • 2 = 332us
  • 3 = 588us
  • 4 = 1.1ms
  • 5 = 2.116ms
  • 6 = 4.156ms
  • 7 = 8.244ms

Advanced Functions

BrickletVoltageCurrentV2.set_calibration
Function ID:
  • 15
Request:
  • voltage_multiplier – Type: uint16, Range: [0 to 216 - 1]
  • voltage_divisor – Type: uint16, Range: [0 to 216 - 1]
  • current_multiplier – Type: uint16, Range: [0 to 216 - 1]
  • current_divisor – Type: uint16, Range: [0 to 216 - 1]
Response:
  • no response

Since the ADC and the shunt resistor used for the measurements are not perfect they need to be calibrated by a multiplier and a divisor if a very precise reading is needed.

For example, if you are expecting a current of 1000mA and you are measuring 1023mA, you can calibrate the Voltage/Current Bricklet by setting the current multiplier to 1000 and the divisor to 1023. The same applies for the voltage.

The calibration will be saved on the EEPROM of the Voltage/Current Bricklet and only needs to be done once.

BrickletVoltageCurrentV2.get_calibration
Function ID:
  • 16
Request:
  • empty payload
Response:
  • voltage_multiplier – Type: uint16, Range: [0 to 216 - 1]
  • voltage_divisor – Type: uint16, Range: [0 to 216 - 1]
  • current_multiplier – Type: uint16, Range: [0 to 216 - 1]
  • current_divisor – Type: uint16, Range: [0 to 216 - 1]

Returns the calibration as set by set_calibration.

BrickletVoltageCurrentV2.get_spitfp_error_count
Function ID:
  • 234
Request:
  • empty payload
Response:
  • error_count_ack_checksum – Type: uint32, Range: [0 to 232 - 1]
  • error_count_message_checksum – Type: uint32, Range: [0 to 232 - 1]
  • error_count_frame – Type: uint32, Range: [0 to 232 - 1]
  • error_count_overflow – Type: uint32, Range: [0 to 232 - 1]

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.

BrickletVoltageCurrentV2.set_bootloader_mode
Function ID:
  • 235
Request:
  • mode – Type: uint8, Range: See meanings
Response:
  • status – Type: uint8, Range: See meanings

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 meanings are defined for the elements of this function:

For mode:

  • 0 = Bootloader
  • 1 = Firmware
  • 2 = Bootloader Wait For Reboot
  • 3 = Firmware Wait For Reboot
  • 4 = Firmware Wait For Erase And Reboot

For status:

  • 0 = OK
  • 1 = Invalid Mode
  • 2 = No Change
  • 3 = Entry Function Not Present
  • 4 = Device Identifier Incorrect
  • 5 = CRC Mismatch
BrickletVoltageCurrentV2.get_bootloader_mode
Function ID:
  • 236
Request:
  • empty payload
Response:
  • mode – Type: uint8, Range: See meanings

Returns the current bootloader mode, see set_bootloader_mode.

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

For mode:

  • 0 = Bootloader
  • 1 = Firmware
  • 2 = Bootloader Wait For Reboot
  • 3 = Firmware Wait For Reboot
  • 4 = Firmware Wait For Erase And Reboot
BrickletVoltageCurrentV2.set_write_firmware_pointer
Function ID:
  • 237
Request:
  • pointer – Type: uint32, Unit: 1 B, Range: [0 to 232 - 1]
Response:
  • no response

Sets the firmware pointer for 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.

BrickletVoltageCurrentV2.write_firmware
Function ID:
  • 238
Request:
  • data – Type: uint8[64], Range: [0 to 255]
Response:
  • status – Type: uint8, Range: [0 to 255]

Writes 64 Bytes of firmware at the position as written by 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.

BrickletVoltageCurrentV2.set_status_led_config
Function ID:
  • 239
Request:
  • config – Type: uint8, Range: See meanings, Default: 3
Response:
  • no response

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 meanings are defined for the elements of this function:

For config:

  • 0 = Off
  • 1 = On
  • 2 = Show Heartbeat
  • 3 = Show Status
BrickletVoltageCurrentV2.get_status_led_config
Function ID:
  • 240
Request:
  • empty payload
Response:
  • config – Type: uint8, Range: See meanings, Default: 3

Returns the configuration as set by set_status_led_config

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

For config:

  • 0 = Off
  • 1 = On
  • 2 = Show Heartbeat
  • 3 = Show Status
BrickletVoltageCurrentV2.get_chip_temperature
Function ID:
  • 242
Request:
  • empty payload
Response:
  • temperature – Type: int16, Unit: 1 °C, Range: [-215 to 215 - 1]

Returns the temperature 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.

BrickletVoltageCurrentV2.reset
Function ID:
  • 243
Request:
  • empty payload
Response:
  • no response

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!

BrickletVoltageCurrentV2.write_uid
Function ID:
  • 248
Request:
  • uid – Type: uint32, Range: [0 to 232 - 1]
Response:
  • no response

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.

BrickletVoltageCurrentV2.read_uid
Function ID:
  • 249
Request:
  • empty payload
Response:
  • uid – Type: uint32, Range: [0 to 232 - 1]

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

BrickletVoltageCurrentV2.get_identity
Function ID:
  • 255
Request:
  • empty payload
Response:
  • uid – Type: char[8]
  • connected_uid – Type: char[8]
  • position – Type: char, Range: ['a' to 'i', 'z']
  • hardware_version – Type: uint8[3]
    • 0: major – Type: uint8, Range: [0 to 255]
    • 1: minor – Type: uint8, Range: [0 to 255]
    • 2: revision – Type: uint8, Range: [0 to 255]
  • firmware_version – Type: uint8[3]
    • 0: major – Type: uint8, Range: [0 to 255]
    • 1: minor – Type: uint8, Range: [0 to 255]
    • 2: revision – Type: uint8, Range: [0 to 255]
  • device_identifier – Type: uint16, Range: [0 to 216 - 1]

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', 'd', 'e', 'f', 'g' or 'h' (Bricklet Port). The Raspberry Pi HAT (Zero) Brick is always at position 'i' and the Bricklet connected to an Isolator Bricklet is always as position 'z'.

The device identifier numbers can be found here

Callback Configuration Functions

BrickletVoltageCurrentV2.set_current_callback_configuration
Function ID:
  • 2
Request:
  • period – Type: uint32, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0
  • value_has_to_change – Type: bool, Default: false
  • option – Type: char, Range: See meanings, Default: 'x'
  • min – Type: int32, Unit: 1 mA, Range: [-231 to 231 - 1], Default: 0
  • max – Type: int32, Unit: 1 mA, Range: [-231 to 231 - 1], Default: 0
Response:
  • no response

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

If the value has to change-parameter is set to true, the callback is only triggered after the value has changed. If the value didn't change within the period, the callback is triggered immediately on change.

If it is set to false, the callback is continuously triggered with the period, independent of the value.

It is furthermore possible to constrain the callback with thresholds.

The option-parameter together with min/max sets a threshold for the CALLBACK_CURRENT callback.

The following options are possible:

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

If the option is set to 'x' (threshold turned off) the callback is triggered with the fixed period.

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

For option:

  • 'x' = Off
  • 'o' = Outside
  • 'i' = Inside
  • '<' = Smaller
  • '>' = Greater
BrickletVoltageCurrentV2.get_current_callback_configuration
Function ID:
  • 3
Request:
  • empty payload
Response:
  • period – Type: uint32, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0
  • value_has_to_change – Type: bool, Default: false
  • option – Type: char, Range: See meanings, Default: 'x'
  • min – Type: int32, Unit: 1 mA, Range: [-231 to 231 - 1], Default: 0
  • max – Type: int32, Unit: 1 mA, Range: [-231 to 231 - 1], Default: 0

Returns the callback configuration as set by set_current_callback_configuration.

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

For option:

  • 'x' = Off
  • 'o' = Outside
  • 'i' = Inside
  • '<' = Smaller
  • '>' = Greater
BrickletVoltageCurrentV2.set_voltage_callback_configuration
Function ID:
  • 6
Request:
  • period – Type: uint32, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0
  • value_has_to_change – Type: bool, Default: false
  • option – Type: char, Range: See meanings, Default: 'x'
  • min – Type: int32, Unit: 1 mV, Range: [-231 to 231 - 1], Default: 0
  • max – Type: int32, Unit: 1 mV, Range: [-231 to 231 - 1], Default: 0
Response:
  • no response

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

If the value has to change-parameter is set to true, the callback is only triggered after the value has changed. If the value didn't change within the period, the callback is triggered immediately on change.

If it is set to false, the callback is continuously triggered with the period, independent of the value.

It is furthermore possible to constrain the callback with thresholds.

The option-parameter together with min/max sets a threshold for the CALLBACK_VOLTAGE callback.

The following options are possible:

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

If the option is set to 'x' (threshold turned off) the callback is triggered with the fixed period.

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

For option:

  • 'x' = Off
  • 'o' = Outside
  • 'i' = Inside
  • '<' = Smaller
  • '>' = Greater
BrickletVoltageCurrentV2.get_voltage_callback_configuration
Function ID:
  • 7
Request:
  • empty payload
Response:
  • period – Type: uint32, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0
  • value_has_to_change – Type: bool, Default: false
  • option – Type: char, Range: See meanings, Default: 'x'
  • min – Type: int32, Unit: 1 mV, Range: [-231 to 231 - 1], Default: 0
  • max – Type: int32, Unit: 1 mV, Range: [-231 to 231 - 1], Default: 0

Returns the callback configuration as set by set_voltage_callback_configuration.

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

For option:

  • 'x' = Off
  • 'o' = Outside
  • 'i' = Inside
  • '<' = Smaller
  • '>' = Greater
BrickletVoltageCurrentV2.set_power_callback_configuration
Function ID:
  • 10
Request:
  • period – Type: uint32, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0
  • value_has_to_change – Type: bool, Default: false
  • option – Type: char, Range: See meanings, Default: 'x'
  • min – Type: int32, Unit: 1 mW, Range: [-231 to 231 - 1], Default: 0
  • max – Type: int32, Unit: 1 mW, Range: [-231 to 231 - 1], Default: 0
Response:
  • no response

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

If the value has to change-parameter is set to true, the callback is only triggered after the value has changed. If the value didn't change within the period, the callback is triggered immediately on change.

If it is set to false, the callback is continuously triggered with the period, independent of the value.

It is furthermore possible to constrain the callback with thresholds.

The option-parameter together with min/max sets a threshold for the CALLBACK_POWER callback.

The following options are possible:

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

If the option is set to 'x' (threshold turned off) the callback is triggered with the fixed period.

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

For option:

  • 'x' = Off
  • 'o' = Outside
  • 'i' = Inside
  • '<' = Smaller
  • '>' = Greater
BrickletVoltageCurrentV2.get_power_callback_configuration
Function ID:
  • 11
Request:
  • empty payload
Response:
  • period – Type: uint32, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0
  • value_has_to_change – Type: bool, Default: false
  • option – Type: char, Range: See meanings, Default: 'x'
  • min – Type: int32, Unit: 1 mW, Range: [-231 to 231 - 1], Default: 0
  • max – Type: int32, Unit: 1 mW, Range: [-231 to 231 - 1], Default: 0

Returns the callback configuration as set by set_power_callback_configuration.

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

For option:

  • 'x' = Off
  • 'o' = Outside
  • 'i' = Inside
  • '<' = Smaller
  • '>' = Greater

Callbacks

BrickletVoltageCurrentV2.CALLBACK_CURRENT
Function ID:
  • 4
Response:
  • current – Type: int32, Unit: 1 mA, Range: [-20000 to 20000]

This callback is triggered periodically according to the configuration set by set_current_callback_configuration.

The response value is the same as get_current.

BrickletVoltageCurrentV2.CALLBACK_VOLTAGE
Function ID:
  • 8
Response:
  • voltage – Type: int32, Unit: 1 mV, Range: [0 to 36000]

This callback is triggered periodically according to the configuration set by set_voltage_callback_configuration.

The response value is the same as get_voltage.

BrickletVoltageCurrentV2.CALLBACK_POWER
Function ID:
  • 12
Response:
  • power – Type: int32, Unit: 1 mW, Range: [0 to 720000]

This callback is triggered periodically according to the configuration set by set_power_callback_configuration.

The response value is the same as get_power.