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

Modbus - PTC Bricklet¶

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

API¶

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

Basic Functions¶

BrickletPTC.get_temperature¶

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

Returns the temperature of connected sensor.

If you want to get the temperature periodically, it is recommended to use the CALLBACK_TEMPERATURE callback and set the period with set_temperature_callback_period.

BrickletPTC.is_sensor_connected¶

Function ID:	19
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.

BrickletPTC.set_wire_mode¶

Function ID:	20
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

BrickletPTC.get_wire_mode¶

Function ID:	21
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

Advanced Functions¶

BrickletPTC.get_resistance¶

Function ID:	2
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 resistance periodically, it is recommended to use the CALLBACK_RESISTANCE callback and set the period with set_resistance_callback_period.

BrickletPTC.set_noise_rejection_filter¶

Function ID:	17
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

BrickletPTC.get_noise_rejection_filter¶

Function ID:	18
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

BrickletPTC.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¶

BrickletPTC.set_temperature_callback_period¶

Function ID:	3
Request:	period – Type: uint32, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 0
Response:	no response

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

The CALLBACK_TEMPERATURE callback is only triggered if the temperature has changed since the last triggering.

BrickletPTC.get_temperature_callback_period¶

Function ID:	4
Request:	empty payload
Response:	period – Type: uint32, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 0

Returns the period as set by set_temperature_callback_period.

BrickletPTC.set_resistance_callback_period¶

Function ID:	5
Request:	period – Type: uint32, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 0
Response:	no response

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

The CALLBACK_RESISTANCE callback is only triggered if the resistance has changed since the last triggering.

BrickletPTC.get_resistance_callback_period¶

Function ID:	6
Request:	empty payload
Response:	period – Type: uint32, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 0

Returns the period as set by set_resistance_callback_period.

BrickletPTC.set_temperature_callback_threshold¶

Function ID:	7
Request:	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

Sets the thresholds for the CALLBACK_TEMPERATURE_REACHED callback.

The following options are possible:

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

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

For option:

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

BrickletPTC.get_temperature_callback_threshold¶

Function ID:	8
Request:	empty payload
Response:	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 threshold as set by set_temperature_callback_threshold.

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

For option:

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

BrickletPTC.set_resistance_callback_threshold¶

Function ID:	9
Request:	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

Sets the thresholds for the CALLBACK_RESISTANCE_REACHED callback.

The following options are possible:

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

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

For option:

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

BrickletPTC.get_resistance_callback_threshold¶

Function ID:	10
Request:	empty payload
Response:	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 threshold as set by set_resistance_callback_threshold.

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

For option:

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

BrickletPTC.set_debounce_period¶

Function ID:	11
Request:	debounce – Type: uint32, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 100
Response:	no response

Sets the period with which the threshold callback

CALLBACK_TEMPERATURE_REACHED,
CALLBACK_RESISTANCE_REACHED

is triggered, if the threshold

set_temperature_callback_threshold,
set_resistance_callback_threshold

keeps being reached.

BrickletPTC.get_debounce_period¶

Function ID:	12
Request:	empty payload
Response:	debounce – Type: uint32, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 100

Returns the debounce period as set by set_debounce_period.

BrickletPTC.set_sensor_connected_callback_configuration¶

Function ID:	22
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.

New in version 2.0.2 (Plugin).

BrickletPTC.get_sensor_connected_callback_configuration¶

Function ID:	23
Request:	empty payload
Response:	enabled – Type: bool, Default: false

Returns the configuration as set by set_sensor_connected_callback_configuration.

New in version 2.0.2 (Plugin).

Callbacks¶

BrickletPTC.CALLBACK_TEMPERATURE¶

Function ID:	13
Response:	temperature – Type: int32, Unit: 1/100 °C, Range: [-24600 to 84900]

This callback is triggered periodically with the period that is set by set_temperature_callback_period. The response value is the temperature of the connected sensor.

The CALLBACK_TEMPERATURE callback is only triggered if the temperature has changed since the last triggering.

BrickletPTC.CALLBACK_TEMPERATURE_REACHED¶

Function ID:	14
Response:	temperature – Type: int32, Unit: 1/100 °C, Range: [-24600 to 84900]

This callback is triggered when the threshold as set by set_temperature_callback_threshold is reached. The response value is the temperature of the connected sensor.

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

BrickletPTC.CALLBACK_RESISTANCE¶

Function ID:	15
Response:	resistance – Type: int32, Unit: ? Ω, Range: [-2³¹ to 2³¹ - 1]

This callback is triggered periodically with the period that is set by set_resistance_callback_period. The response value is the resistance of the connected sensor.

The CALLBACK_RESISTANCE callback is only triggered if the resistance has changed since the last triggering.

BrickletPTC.CALLBACK_RESISTANCE_REACHED¶

Function ID:	16
Response:	resistance – Type: int32, Unit: ? Ω, Range: [-2³¹ to 2³¹ - 1]

This callback is triggered when the threshold as set by set_resistance_callback_threshold is reached. The response value is the resistance of the connected sensor.

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

BrickletPTC.CALLBACK_SENSOR_CONNECTED¶

Function ID:	24
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.

New in version 2.0.2 (Plugin).