Specifications / Modbus Protocol / API / Bricklets (Discontinued) / PTC Bricklet 2.0

Modbus - PTC Bricklet 2.0¶

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

API¶

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

Basic Functions¶

BrickletPTCV2.get_temperature¶

Function ID:	1
Request:	empty payload
Response:	temperature – Type: int32, Unit: 1/100 °C, Range: [-24600 to 84900]

Returns the temperature of the connected sensor.

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

BrickletPTCV2.get_resistance¶

Function ID:	5
Request:	empty payload
Response:	resistance – Type: int32, Unit: ? Ω, Range: [-2³¹ to 2³¹ - 1]

Returns the value as measured by the MAX31865 precision delta-sigma ADC.

The value can be converted with the following formulas:

Pt100: resistance = (value * 390) / 32768
Pt1000: resistance = (value * 3900) / 32768

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

BrickletPTCV2.is_sensor_connected¶

Function ID:	11
Request:	empty payload
Response:	connected – Type: bool

Returns true if the sensor is connected correctly.

If this function returns false, there is either no Pt100 or Pt1000 sensor connected, the sensor is connected incorrectly or the sensor itself is faulty.

If you want to get the status automatically, it is recommended to use the CALLBACK_SENSOR_CONNECTED callback. You can set the callback configuration with set_sensor_connected_callback_configuration.

BrickletPTCV2.set_wire_mode¶

Function ID:	12
Request:	mode – Type: uint8, Range: See meanings, Default: 2
Response:	no response

Sets the wire mode of the sensor. Possible values are 2, 3 and 4 which correspond to 2-, 3- and 4-wire sensors. The value has to match the jumper configuration on the Bricklet.

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

For mode:

2 = 2
3 = 3
4 = 4

BrickletPTCV2.get_wire_mode¶

Function ID:	13
Request:	empty payload
Response:	mode – Type: uint8, Range: See meanings, Default: 2

Returns the wire mode as set by set_wire_mode

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

For mode:

2 = 2
3 = 3
4 = 4

BrickletPTCV2.set_moving_average_configuration¶

Function ID:	14
Request:	moving_average_length_resistance – Type: uint16, Range: [1 to 1000], Default: 1 moving_average_length_temperature – Type: uint16, Range: [1 to 1000], Default: 40
Response:	no response

Sets the length of a moving averaging for the resistance and temperature.

Setting the length to 1 will turn the averaging off. With less averaging, there is more noise on the data.

New data is gathered every 20ms. With a moving average of length 1000 the resulting averaging window has a length of 20s. If you want to do long term measurements the longest moving average will give the cleanest results.

The default values match the non-changeable averaging settings of the old PTC Bricklet 1.0

BrickletPTCV2.get_moving_average_configuration¶

Function ID:	15
Request:	empty payload
Response:	moving_average_length_resistance – Type: uint16, Range: [1 to 1000], Default: 1 moving_average_length_temperature – Type: uint16, Range: [1 to 1000], Default: 40

Returns the moving average configuration as set by set_moving_average_configuration.

Advanced Functions¶

BrickletPTCV2.set_noise_rejection_filter¶

Function ID:	9
Request:	filter – Type: uint8, Range: See meanings, Default: 0
Response:	no response

Sets the noise rejection filter to either 50Hz (0) or 60Hz (1). Noise from 50Hz or 60Hz power sources (including harmonics of the AC power's fundamental frequency) is attenuated by 82dB.

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

For filter:

0 = 50Hz
1 = 60Hz

BrickletPTCV2.get_noise_rejection_filter¶

Function ID:	10
Request:	empty payload
Response:	filter – Type: uint8, Range: See meanings, Default: 0

Returns the noise rejection filter option as set by set_noise_rejection_filter

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

For filter:

0 = 50Hz
1 = 60Hz

BrickletPTCV2.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.

BrickletPTCV2.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

BrickletPTCV2.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

BrickletPTCV2.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.

BrickletPTCV2.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!

BrickletPTCV2.get_identity¶

Function ID:	255
Request:	empty payload
Response:	uid – Type: char[8] connected_uid – Type: char[8] position – Type: char, Range: ['a' to 'h', '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). A Bricklet connected to an Isolator Bricklet is always at position 'z'.

The device identifier numbers can be found here.

Callback Configuration Functions¶

BrickletPTCV2.set_temperature_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: 1/100 °C, Range: [-2³¹ to 2³¹ - 1], Default: 0 max – Type: int32, Unit: 1/100 °C, Range: [-2³¹ to 2³¹ - 1], Default: 0
Response:	no response

The period is the period with which the CALLBACK_TEMPERATURE 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_TEMPERATURE 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

BrickletPTCV2.get_temperature_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: 1/100 °C, Range: [-2³¹ to 2³¹ - 1], Default: 0 max – Type: int32, Unit: 1/100 °C, Range: [-2³¹ to 2³¹ - 1], Default: 0

Returns the callback configuration as set by set_temperature_callback_configuration.

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

For option:

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

BrickletPTCV2.set_resistance_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: ? Ω, Range: [-2³¹ to 2³¹ - 1], Default: 0 max – Type: int32, Unit: ? Ω, Range: [-2³¹ to 2³¹ - 1], Default: 0
Response:	no response

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

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_RESISTANCE 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

BrickletPTCV2.get_resistance_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: ? Ω, Range: [-2³¹ to 2³¹ - 1], Default: 0 max – Type: int32, Unit: ? Ω, Range: [-2³¹ to 2³¹ - 1], Default: 0

Returns the callback configuration as set by set_resistance_callback_configuration.

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

For option:

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

BrickletPTCV2.set_sensor_connected_callback_configuration¶

Function ID:	16
Request:	enabled – Type: bool, Default: false
Response:	no response

If you enable this callback, the CALLBACK_SENSOR_CONNECTED callback is triggered every time a Pt sensor is connected/disconnected.

BrickletPTCV2.get_sensor_connected_callback_configuration¶

Function ID:	17
Request:	empty payload
Response:	enabled – Type: bool, Default: false

Returns the configuration as set by set_sensor_connected_callback_configuration.

Callbacks¶

BrickletPTCV2.CALLBACK_TEMPERATURE¶

Function ID:	4
Response:	temperature – Type: int32, Unit: 1/100 °C, Range: [-24600 to 84900]

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

The response value is the same as get_temperature.

BrickletPTCV2.CALLBACK_RESISTANCE¶

Function ID:	8
Response:	resistance – Type: int32, Unit: ? Ω, Range: [-2³¹ to 2³¹ - 1]

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

The response value is the same as get_resistance.

BrickletPTCV2.CALLBACK_SENSOR_CONNECTED¶

Function ID:	18
Response:	connected – Type: bool

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

The response value is the same as is_sensor_connected.

Internal Functions¶

Internal functions are used for maintenance tasks such as flashing a new firmware of changing the UID of a Bricklet. These task should be performed using Brick Viewer instead of using the internal functions directly.

BrickletPTCV2.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

BrickletPTCV2.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

BrickletPTCV2.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.

BrickletPTCV2.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.

BrickletPTCV2.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.

BrickletPTCV2.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.