Software / API Bindings / Python / API Reference and Examples / Bricklets (Discontinued) / PTC Bricklet

Python - PTC Bricklet¶

This is the description of the Python API bindings for the PTC Bricklet. General information and technical specifications for the PTC Bricklet are summarized in its hardware description.

An installation guide for the Python API bindings is part of their general description.

Examples¶

The example code below is Public Domain (CC0 1.0).

Simple¶

Download (example_simple.py)

#!/usr/bin/env python
# -*- coding: utf-8 -*-

HOST = "localhost"
PORT = 4223
UID = "XYZ" # Change XYZ to the UID of your PTC Bricklet

from tinkerforge.ip_connection import IPConnection
from tinkerforge.bricklet_ptc import BrickletPTC

if __name__ == "__main__":
    ipcon = IPConnection() # Create IP connection
    ptc = BrickletPTC(UID, ipcon) # Create device object

    ipcon.connect(HOST, PORT) # Connect to brickd
    # Don't use device before ipcon is connected

    # Get current temperature
    temperature = ptc.get_temperature()
    print("Temperature: " + str(temperature/100.0) + " °C")

    input("Press key to exit\n") # Use raw_input() in Python 2
    ipcon.disconnect()

Callback¶

Download (example_callback.py)

#!/usr/bin/env python
# -*- coding: utf-8 -*-

HOST = "localhost"
PORT = 4223
UID = "XYZ" # Change XYZ to the UID of your PTC Bricklet

from tinkerforge.ip_connection import IPConnection
from tinkerforge.bricklet_ptc import BrickletPTC

# Callback function for temperature callback
def cb_temperature(temperature):
    print("Temperature: " + str(temperature/100.0) + " °C")

if __name__ == "__main__":
    ipcon = IPConnection() # Create IP connection
    ptc = BrickletPTC(UID, ipcon) # Create device object

    ipcon.connect(HOST, PORT) # Connect to brickd
    # Don't use device before ipcon is connected

    # Register temperature callback to function cb_temperature
    ptc.register_callback(ptc.CALLBACK_TEMPERATURE, cb_temperature)

    # Set period for temperature callback to 1s (1000ms)
    # Note: The temperature callback is only called every second
    #       if the temperature has changed since the last call!
    ptc.set_temperature_callback_period(1000)

    input("Press key to exit\n") # Use raw_input() in Python 2
    ipcon.disconnect()

Threshold¶

Download (example_threshold.py)

#!/usr/bin/env python
# -*- coding: utf-8 -*-

HOST = "localhost"
PORT = 4223
UID = "XYZ" # Change XYZ to the UID of your PTC Bricklet

from tinkerforge.ip_connection import IPConnection
from tinkerforge.bricklet_ptc import BrickletPTC

# Callback function for temperature reached callback
def cb_temperature_reached(temperature):
    print("Temperature: " + str(temperature/100.0) + " °C")

if __name__ == "__main__":
    ipcon = IPConnection() # Create IP connection
    ptc = BrickletPTC(UID, ipcon) # Create device object

    ipcon.connect(HOST, PORT) # Connect to brickd
    # Don't use device before ipcon is connected

    # Get threshold callbacks with a debounce time of 10 seconds (10000ms)
    ptc.set_debounce_period(10000)

    # Register temperature reached callback to function cb_temperature_reached
    ptc.register_callback(ptc.CALLBACK_TEMPERATURE_REACHED, cb_temperature_reached)

    # Configure threshold for temperature "greater than 30 °C"
    ptc.set_temperature_callback_threshold(">", 30*100, 0)

    input("Press key to exit\n") # Use raw_input() in Python 2
    ipcon.disconnect()

API¶

Generally, every function of the Python bindings can throw an tinkerforge.ip_connection.Error exception that has a value and a description property. value can have different values:

Error.TIMEOUT = -1
Error.NOT_ADDED = -6 (unused since Python bindings version 2.0.0)
Error.ALREADY_CONNECTED = -7
Error.NOT_CONNECTED = -8
Error.INVALID_PARAMETER = -9
Error.NOT_SUPPORTED = -10
Error.UNKNOWN_ERROR_CODE = -11
Error.STREAM_OUT_OF_SYNC = -12
Error.INVALID_UID = -13
Error.NON_ASCII_CHAR_IN_SECRET = -14
Error.WRONG_DEVICE_TYPE = -15
Error.DEVICE_REPLACED = -16
Error.WRONG_RESPONSE_LENGTH = -17

All functions listed below are thread-safe.

Basic Functions¶

BrickletPTC(uid, ipcon)¶

Parameters:	uid – Type: str ipcon – Type: IPConnection
Returns:	ptc – Type: BrickletPTC

Creates an object with the unique device ID uid:

ptc = BrickletPTC("YOUR_DEVICE_UID", ipcon)

This object can then be used after the IP Connection is connected.

BrickletPTC.get_temperature()¶

Returns:	temperature – Type: int, 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()¶

Returns:	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(mode)¶

Parameters:	mode – Type: int, Range: See constants, Default: 2
Returns:	None

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 constants are available for this function:

For mode:

BrickletPTC.WIRE_MODE_2 = 2
BrickletPTC.WIRE_MODE_3 = 3
BrickletPTC.WIRE_MODE_4 = 4

BrickletPTC.get_wire_mode()¶

Returns:	mode – Type: int, Range: See constants, Default: 2

Returns the wire mode as set by set_wire_mode()

The following constants are available for this function:

For mode:

BrickletPTC.WIRE_MODE_2 = 2
BrickletPTC.WIRE_MODE_3 = 3
BrickletPTC.WIRE_MODE_4 = 4

Advanced Functions¶

BrickletPTC.get_resistance()¶

Returns:	resistance – Type: int, 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(filter)¶

Parameters:	filter – Type: int, Range: See constants, Default: 0
Returns:	None

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 constants are available for this function:

For filter:

BrickletPTC.FILTER_OPTION_50HZ = 0
BrickletPTC.FILTER_OPTION_60HZ = 1

BrickletPTC.get_noise_rejection_filter()¶

Returns:	filter – Type: int, Range: See constants, Default: 0

Returns the noise rejection filter option as set by set_noise_rejection_filter()

The following constants are available for this function:

For filter:

BrickletPTC.FILTER_OPTION_50HZ = 0
BrickletPTC.FILTER_OPTION_60HZ = 1

BrickletPTC.get_identity()¶

Return Object:

Return Object:	uid – Type: str, Length: up to 8 connected_uid – Type: str, Length: up to 8 position – Type: chr, Range: ["a" to "h", "z"] hardware_version – Type: [int, ...], Length: 3 0: major – Type: int, Range: [0 to 255] 1: minor – Type: int, Range: [0 to 255] 2: revision – Type: int, Range: [0 to 255] firmware_version – Type: [int, ...], Length: 3 0: major – Type: int, Range: [0 to 255] 1: minor – Type: int, Range: [0 to 255] 2: revision – Type: int, Range: [0 to 255] device_identifier – Type: int, Range: [0 to 2¹⁶ - 1]

uid – Type: str, Length: up to 8
connected_uid – Type: str, Length: up to 8
position – Type: chr, Range: ["a" to "h", "z"]
hardware_version – Type: [int, ...], Length: 3

0: major – Type: int, Range: [0 to 255]
1: minor – Type: int, Range: [0 to 255]
2: revision – Type: int, Range: [0 to 255]

firmware_version – Type: [int, ...], Length: 3

0: major – Type: int, Range: [0 to 255]
1: minor – Type: int, Range: [0 to 255]
2: revision – Type: int, Range: [0 to 255]

device_identifier – Type: int, 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. There is also a constant for the device identifier of this Bricklet.

Callback Configuration Functions¶

BrickletPTC.register_callback(callback_id, function)¶

Parameters:	callback_id – Type: int function – Type: callable
Returns:	None

Registers the given function with the given callback_id.

The available callback IDs with corresponding function signatures are listed below.

BrickletPTC.set_temperature_callback_period(period)¶

Parameters:	period – Type: int, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 0
Returns:	None

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()¶

Returns:	period – Type: int, 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(period)¶

Parameters:	period – Type: int, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 0
Returns:	None

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()¶

Returns:	period – Type: int, 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(option, min, max)¶

Parameters:	option – Type: chr, Range: See constants, Default: "x" min – Type: int, Unit: 1/100 °C, Range: [-2³¹ to 2³¹ - 1], Default: 0 max – Type: int, Unit: 1/100 °C, Range: [-2³¹ to 2³¹ - 1], Default: 0
Returns:	None

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 constants are available for this function:

For option:

BrickletPTC.THRESHOLD_OPTION_OFF = "x"
BrickletPTC.THRESHOLD_OPTION_OUTSIDE = "o"
BrickletPTC.THRESHOLD_OPTION_INSIDE = "i"
BrickletPTC.THRESHOLD_OPTION_SMALLER = "<"
BrickletPTC.THRESHOLD_OPTION_GREATER = ">"

BrickletPTC.get_temperature_callback_threshold()¶

Return Object:	option – Type: chr, Range: See constants, Default: "x" min – Type: int, Unit: 1/100 °C, Range: [-2³¹ to 2³¹ - 1], Default: 0 max – Type: int, Unit: 1/100 °C, Range: [-2³¹ to 2³¹ - 1], Default: 0

Returns the threshold as set by set_temperature_callback_threshold().

The following constants are available for this function:

For option:

BrickletPTC.THRESHOLD_OPTION_OFF = "x"
BrickletPTC.THRESHOLD_OPTION_OUTSIDE = "o"
BrickletPTC.THRESHOLD_OPTION_INSIDE = "i"
BrickletPTC.THRESHOLD_OPTION_SMALLER = "<"
BrickletPTC.THRESHOLD_OPTION_GREATER = ">"

BrickletPTC.set_resistance_callback_threshold(option, min, max)¶

Parameters:	option – Type: chr, Range: See constants, Default: "x" min – Type: int, Unit: ? Ω, Range: [-2³¹ to 2³¹ - 1], Default: 0 max – Type: int, Unit: ? Ω, Range: [-2³¹ to 2³¹ - 1], Default: 0
Returns:	None

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 constants are available for this function:

For option:

BrickletPTC.THRESHOLD_OPTION_OFF = "x"
BrickletPTC.THRESHOLD_OPTION_OUTSIDE = "o"
BrickletPTC.THRESHOLD_OPTION_INSIDE = "i"
BrickletPTC.THRESHOLD_OPTION_SMALLER = "<"
BrickletPTC.THRESHOLD_OPTION_GREATER = ">"

BrickletPTC.get_resistance_callback_threshold()¶

Return Object:	option – Type: chr, Range: See constants, Default: "x" min – Type: int, Unit: ? Ω, Range: [-2³¹ to 2³¹ - 1], Default: 0 max – Type: int, Unit: ? Ω, Range: [-2³¹ to 2³¹ - 1], Default: 0

Returns the threshold as set by set_resistance_callback_threshold().

The following constants are available for this function:

For option:

BrickletPTC.THRESHOLD_OPTION_OFF = "x"
BrickletPTC.THRESHOLD_OPTION_OUTSIDE = "o"
BrickletPTC.THRESHOLD_OPTION_INSIDE = "i"
BrickletPTC.THRESHOLD_OPTION_SMALLER = "<"
BrickletPTC.THRESHOLD_OPTION_GREATER = ">"

BrickletPTC.set_debounce_period(debounce)¶

Parameters:	debounce – Type: int, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 100
Returns:	None

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()¶

Returns:	debounce – Type: int, 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(enabled)¶

Parameters:	enabled – Type: bool, Default: False
Returns:	None

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()¶

Returns:	enabled – Type: bool, Default: False

Returns the configuration as set by set_sensor_connected_callback_configuration().

New in version 2.0.2 (Plugin).

Callbacks¶

Callbacks can be registered to receive time critical or recurring data from the device. The registration is done with the register_callback() function of the device object. The first parameter is the callback ID and the second parameter the callback function:

def my_callback(param):
    print(param)

ptc.register_callback(BrickletPTC.CALLBACK_EXAMPLE, my_callback)

The available constants with inherent number and type of parameters are described below.

Note

Using callbacks for recurring events is always preferred compared to using getters. It will use less USB bandwidth and the latency will be a lot better, since there is no round trip time.

BrickletPTC.CALLBACK_TEMPERATURE¶

Callback Parameters:	temperature – Type: int, 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 parameter 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¶

Callback Parameters:	temperature – Type: int, 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 parameter 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¶

Callback Parameters:	resistance – Type: int, Unit: ? Ω, Range: [-2³¹ to 2³¹ - 1]

This callback is triggered periodically with the period that is set by set_resistance_callback_period(). The parameter 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¶

Callback Parameters:	resistance – Type: int, Unit: ? Ω, Range: [-2³¹ to 2³¹ - 1]

This callback is triggered when the threshold as set by set_resistance_callback_threshold() is reached. The parameter 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¶

Callback Parameters:	connected – Type: bool

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

The parameter is the same as is_sensor_connected().

New in version 2.0.2 (Plugin).

Virtual Functions¶

Virtual functions don't communicate with the device itself, but operate only on the API bindings device object. They can be called without the corresponding IP Connection object being connected.

BrickletPTC.get_api_version()¶

Return Object:	api_version – Type: [int, ...], Length: 3 0: major – Type: int, Range: [0 to 255] 1: minor – Type: int, Range: [0 to 255] 2: revision – Type: int, Range: [0 to 255]

Returns the version of the API definition implemented by this API bindings. This is neither the release version of this API bindings nor does it tell you anything about the represented Brick or Bricklet.

BrickletPTC.get_response_expected(function_id)¶

Parameters:	function_id – Type: int, Range: See constants
Returns:	response_expected – Type: bool

Returns the response expected flag for the function specified by the function ID parameter. It is true if the function is expected to send a response, false otherwise.

For getter functions this is enabled by default and cannot be disabled, because those functions will always send a response. For callback configuration functions it is enabled by default too, but can be disabled by set_response_expected(). For setter functions it is disabled by default and can be enabled.

Enabling the response expected flag for a setter function allows to detect timeouts and other error conditions calls of this setter as well. The device will then send a response for this purpose. If this flag is disabled for a setter function then no response is sent and errors are silently ignored, because they cannot be detected.

The following constants are available for this function:

For function_id:

BrickletPTC.FUNCTION_SET_TEMPERATURE_CALLBACK_PERIOD = 3
BrickletPTC.FUNCTION_SET_RESISTANCE_CALLBACK_PERIOD = 5
BrickletPTC.FUNCTION_SET_TEMPERATURE_CALLBACK_THRESHOLD = 7
BrickletPTC.FUNCTION_SET_RESISTANCE_CALLBACK_THRESHOLD = 9
BrickletPTC.FUNCTION_SET_DEBOUNCE_PERIOD = 11
BrickletPTC.FUNCTION_SET_NOISE_REJECTION_FILTER = 17
BrickletPTC.FUNCTION_SET_WIRE_MODE = 20
BrickletPTC.FUNCTION_SET_SENSOR_CONNECTED_CALLBACK_CONFIGURATION = 22

BrickletPTC.set_response_expected(function_id, response_expected)¶

Parameters:	function_id – Type: int, Range: See constants response_expected – Type: bool
Returns:	None

Changes the response expected flag of the function specified by the function ID parameter. This flag can only be changed for setter (default value: false) and callback configuration functions (default value: true). For getter functions it is always enabled.

The following constants are available for this function:

For function_id:

BrickletPTC.FUNCTION_SET_TEMPERATURE_CALLBACK_PERIOD = 3
BrickletPTC.FUNCTION_SET_RESISTANCE_CALLBACK_PERIOD = 5
BrickletPTC.FUNCTION_SET_TEMPERATURE_CALLBACK_THRESHOLD = 7
BrickletPTC.FUNCTION_SET_RESISTANCE_CALLBACK_THRESHOLD = 9
BrickletPTC.FUNCTION_SET_DEBOUNCE_PERIOD = 11
BrickletPTC.FUNCTION_SET_NOISE_REJECTION_FILTER = 17
BrickletPTC.FUNCTION_SET_WIRE_MODE = 20
BrickletPTC.FUNCTION_SET_SENSOR_CONNECTED_CALLBACK_CONFIGURATION = 22

BrickletPTC.set_response_expected_all(response_expected)¶

Parameters:	response_expected – Type: bool
Returns:	None

Changes the response expected flag for all setter and callback configuration functions of this device at once.

Constants¶

BrickletPTC.DEVICE_IDENTIFIER¶

This constant is used to identify a PTC Bricklet.

The get_identity() function and the IPConnection.CALLBACK_ENUMERATE callback of the IP Connection have a device_identifier parameter to specify the Brick's or Bricklet's type.

BrickletPTC.DEVICE_DISPLAY_NAME¶: This constant represents the human readable name of a PTC Bricklet.