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.
The example code below is Public Domain (CC0 1.0).
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 | #!/usr/bin/env python
# -*- coding: utf-8 -*-
HOST = "localhost"
PORT = 4223
UID = "XYZ" # Change to your UID
from tinkerforge.ip_connection import IPConnection
from tinkerforge.bricklet_ptc import PTC
if __name__ == "__main__":
ipcon = IPConnection() # Create IP connection
ptc = PTC(UID, ipcon) # Create device object
ipcon.connect(HOST, PORT) # Connect to brickd
# Don't use device before ipcon is connected
# Get current temperature (unit is °C/100)
temperature = ptc.get_temperature()/100.0
print('Temperature: ' + str(temperature) + ' °C')
raw_input('Press key to exit\n') # Use input() in Python 3
ipcon.disconnect()
|
Download (example_callback.py)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 | #!/usr/bin/env python
# -*- coding: utf-8 -*-
HOST = "localhost"
PORT = 4223
UID = "XYZ" # Change to your UID
from tinkerforge.ip_connection import IPConnection
from tinkerforge.bricklet_ptc import PTC
# Callback function for temperature callback (parameter has unit °C/100)
def cb_temperature(temperature):
print('Temperature: ' + str(temperature/100.0) + ' °C')
if __name__ == "__main__":
ipcon = IPConnection() # Create IP connection
ptc = PTC(UID, ipcon) # Create device object
ipcon.connect(HOST, PORT) # Connect to brickd
# Don't use device before ipcon is connected
# Set Period for temperature callback to 1s (1000ms)
# Note: The callback is only called every second if the
# temperature has changed since the last call!
ptc.set_temperature_callback_period(1000)
# Register temperature callback to function cb_temperature
ptc.register_callback(ptc.CALLBACK_TEMPERATURE, cb_temperature)
raw_input('Press key to exit\n') # Use input() in Python 3
ipcon.disconnect()
|
Download (example_threshold.py)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 | #!/usr/bin/env python
# -*- coding: utf-8 -*-
HOST = "localhost"
PORT = 4223
UID = "XYZ" # Change to your UID
from tinkerforge.ip_connection import IPConnection
from tinkerforge.bricklet_ptc import PTC
# Callback for temperature greater than 30 °C
def cb_reached(temperature):
print('We have ' + str(temperature/100.0) + ' °C.')
print('It is too hot, we need air conditioning!')
if __name__ == "__main__":
ipcon = IPConnection() # Create IP connection
ptc = PTC(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 threshold reached callback to function cb_reached
ptc.register_callback(ptc.CALLBACK_TEMPERATURE_REACHED, cb_reached)
# Configure threshold for "greater than 30 °C" (unit is °C/100)
ptc.set_temperature_callback_threshold('>', 30*100, 0)
raw_input('Press key to exit\n') # Use input() in Python 3
ipcon.disconnect()
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Generally, every method 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:
All methods listed below are thread-safe.
Parameters: |
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Creates an object with the unique device ID uid:
ptc = PTC("YOUR_DEVICE_UID", ipcon)
This object can then be used after the IP Connection is connected (see examples above).
Return type: | int |
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Returns the temperature of connected sensor. The value has a range of -246 to 849 °C and is given in °C/100, e.g. a value of 4223 means that a temperature of 42.23 °C is measured.
If you want to get the temperature periodically, it is recommended to use the callback CALLBACK_TEMPERATURE and set the period with set_temperature_callback_period().
Return type: | bool |
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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.
Parameters: | mode -- int |
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Return type: | 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 default value is 2 = 2-wire.
The following constants are available for this function:
Return type: | int |
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Returns the wire mode as set by set_wire_mode()
The following constants are available for this function:
Return type: | int |
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Returns the value as measured by the MAX31865 precision delta-sigma ADC.
The value can be converted with the following formulas:
If you want to get the resistance periodically, it is recommended to use the callback CALLBACK_RESISTANCE and set the period with set_resistance_callback_period().
Parameters: | filter -- int |
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Return type: | 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.
Default value is 0 = 50Hz.
The following constants are available for this function:
Return type: | int |
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Returns the noise rejection filter option as set by set_noise_rejection_filter()
The following constants are available for this function:
Return type: | [int, int, int] |
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Returns the version of the API definition (major, minor, revision) 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.
Parameters: | function_id -- int |
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Return 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 send and errors are silently ignored, because they cannot be detected.
See set_response_expected() for the list of function ID constants available for this function.
Parameters: |
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Return type: | 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 and callbacks it is always disabled.
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 send and errors are silently ignored, because they cannot be detected.
The following function ID constants are available for this function:
Parameters: | response_expected -- bool |
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Return type: | None |
Changes the response expected flag for all setter and callback configuration functions of this device at once.
Return type: | (str, str, chr, [int, int, int], [int, int, int], int) |
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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. There is also a constant for the device identifier of this Bricklet.
The returned namedtuple has the variables uid, connected_uid, position, hardware_version, firmware_version and device_identifier.
Parameters: |
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Return type: | None |
Registers a callback with ID id to the function callback. The available IDs with corresponding function signatures are listed below.
Parameters: | period -- int |
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Return type: | None |
Sets the period in ms with which the CALLBACK_TEMPERATURE callback is triggered periodically. A value of 0 turns the callback off.
CALLBACK_TEMPERATURE is only triggered if the temperature has changed since the last triggering.
The default value is 0.
Return type: | int |
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Returns the period as set by set_temperature_callback_period().
Parameters: | period -- int |
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Return type: | None |
Sets the period in ms with which the CALLBACK_RESISTANCE callback is triggered periodically. A value of 0 turns the callback off.
CALLBACK_RESISTANCE is only triggered if the resistance has changed since the last triggering.
The default value is 0.
Return type: | int |
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Returns the period as set by set_resistance_callback_period().
Parameters: |
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Return type: | 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 default value is ('x', 0, 0).
The following constants are available for this function:
Return type: | (chr, int, int) |
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Returns the threshold as set by set_temperature_callback_threshold().
The following constants are available for this function:
The returned namedtuple has the variables option, min and max.
Parameters: |
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Return type: | 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 default value is ('x', 0, 0).
The following constants are available for this function:
Return type: | (chr, int, int) |
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Returns the threshold as set by set_resistance_callback_threshold().
The following constants are available for this function:
The returned namedtuple has the variables option, min and max.
Parameters: | debounce -- int |
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Return type: | None |
Sets the period in ms with which the threshold callback
is triggered, if the threshold
keeps being reached.
The default value is 100.
Return type: | int |
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Returns the debounce period as set by set_debounce_period().
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(PTC.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.
Parameters: | temperature -- int |
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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.
CALLBACK_TEMPERATURE is only triggered if the temperature has changed since the last triggering.
Parameters: | temperature -- int |
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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().
Parameters: | resistance -- int |
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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.
CALLBACK_RESISTANCE is only triggered if the resistance has changed since the last triggering.
Parameters: | resistance -- int |
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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().
This constant is used to identify a PTC Bricklet.
The get_identity() function and the CALLBACK_ENUMERATE callback of the IP Connection have a device_identifier parameter to specify the Brick's or Bricklet's type.