PHP - Thermocouple Bricklet

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

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

Examples

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

Simple

Download (ExampleSimple.php)

 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
<?php

require_once('Tinkerforge/IPConnection.php');
require_once('Tinkerforge/BrickletThermocouple.php');

use Tinkerforge\IPConnection;
use Tinkerforge\BrickletThermocouple;

const HOST = 'localhost';
const PORT = 4223;
const UID = 'XYZ'; // Change XYZ to the UID of your Thermocouple Bricklet

$ipcon = new IPConnection(); // Create IP connection
$t = new BrickletThermocouple(UID, $ipcon); // Create device object

$ipcon->connect(HOST, PORT); // Connect to brickd
// Don't use device before ipcon is connected

// Get current temperature
$temperature = $t->getTemperature();
echo "Temperature: " . $temperature/100.0 . " °C\n";

echo "Press key to exit\n";
fgetc(fopen('php://stdin', 'r'));
$ipcon->disconnect();

?>

Callback

Download (ExampleCallback.php)

 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
34
35
36
<?php

require_once('Tinkerforge/IPConnection.php');
require_once('Tinkerforge/BrickletThermocouple.php');

use Tinkerforge\IPConnection;
use Tinkerforge\BrickletThermocouple;

const HOST = 'localhost';
const PORT = 4223;
const UID = 'XYZ'; // Change XYZ to the UID of your Thermocouple Bricklet

// Callback function for temperature callback
function cb_temperature($temperature)
{
    echo "Temperature: " . $temperature/100.0 . " °C\n";
}

$ipcon = new IPConnection(); // Create IP connection
$t = new BrickletThermocouple(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
$t->registerCallback(BrickletThermocouple::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!
$t->setTemperatureCallbackPeriod(1000);

echo "Press ctrl+c to exit\n";
$ipcon->dispatchCallbacks(-1); // Dispatch callbacks forever

?>

Threshold

Download (ExampleThreshold.php)

 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
34
35
36
37
38
<?php

require_once('Tinkerforge/IPConnection.php');
require_once('Tinkerforge/BrickletThermocouple.php');

use Tinkerforge\IPConnection;
use Tinkerforge\BrickletThermocouple;

const HOST = 'localhost';
const PORT = 4223;
const UID = 'XYZ'; // Change XYZ to the UID of your Thermocouple Bricklet

// Callback function for temperature reached callback
function cb_temperatureReached($temperature)
{
    echo "Temperature: " . $temperature/100.0 . " °C\n";
}

$ipcon = new IPConnection(); // Create IP connection
$t = new BrickletThermocouple(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)
$t->setDebouncePeriod(10000);

// Register temperature reached callback to function cb_temperatureReached
$t->registerCallback(BrickletThermocouple::CALLBACK_TEMPERATURE_REACHED,
                     'cb_temperatureReached');

// Configure threshold for temperature "greater than 30 °C"
$t->setTemperatureCallbackThreshold('>', 30*100, 0);

echo "Press ctrl+c to exit\n";
$ipcon->dispatchCallbacks(-1); // Dispatch callbacks forever

?>

API

Functions that return multiple values return them in an associative array.

Basic Functions

class BrickletThermocouple(string $uid, IPConnection $ipcon)
Parameters:
  • $uid – Type: string
  • $ipcon – Type: IPConnection
Returns:
  • $thermocouple – Type: BrickletThermocouple

Creates an object with the unique device ID $uid:

<?php   $thermocouple = new BrickletThermocouple('YOUR_DEVICE_UID', $ipcon);   ?>

This object can then be used after the IP Connection is connected (see examples above).

int BrickletThermocouple::getTemperature()
Returns:
  • $temperature – Type: int, Range: [-231 to 231 - 1]

Returns the temperature of the thermocouple. The value 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_TEMPERATURE callback and set the period with setTemperatureCallbackPeriod().

Advanced Functions

void BrickletThermocouple::setConfiguration(int $averaging, int $thermocouple_type, int $filter)
Parameters:
  • $averaging – Type: int, Range: See constants
  • $thermocouple_type – Type: int, Range: See constants
  • $filter – Type: int, Range: See constants

You can configure averaging size, thermocouple type and frequency filtering.

Available averaging sizes are 1, 2, 4, 8 and 16 samples.

As thermocouple type you can use B, E, J, K, N, R, S and T. If you have a different thermocouple or a custom thermocouple you can also use G8 and G32. With these types the returned value will not be in °C/100, it will be calculated by the following formulas:

  • G8: value = 8 * 1.6 * 2^17 * Vin
  • G32: value = 32 * 1.6 * 2^17 * Vin

where Vin is the thermocouple input voltage.

The frequency filter can be either configured to 50Hz or to 60Hz. You should configure it according to your utility frequency.

The conversion time depends on the averaging and filter configuration, it can be calculated as follows:

  • 60Hz: time = 82 + (samples - 1) * 16.67
  • 50Hz: time = 98 + (samples - 1) * 20

The default configuration is 16 samples, K type and 50Hz.

The following constants are available for this function:

For $averaging:

  • BrickletThermocouple::AVERAGING_1 = 1
  • BrickletThermocouple::AVERAGING_2 = 2
  • BrickletThermocouple::AVERAGING_4 = 4
  • BrickletThermocouple::AVERAGING_8 = 8
  • BrickletThermocouple::AVERAGING_16 = 16

For $thermocouple_type:

  • BrickletThermocouple::TYPE_B = 0
  • BrickletThermocouple::TYPE_E = 1
  • BrickletThermocouple::TYPE_J = 2
  • BrickletThermocouple::TYPE_K = 3
  • BrickletThermocouple::TYPE_N = 4
  • BrickletThermocouple::TYPE_R = 5
  • BrickletThermocouple::TYPE_S = 6
  • BrickletThermocouple::TYPE_T = 7
  • BrickletThermocouple::TYPE_G8 = 8
  • BrickletThermocouple::TYPE_G32 = 9

For $filter:

  • BrickletThermocouple::FILTER_OPTION_50HZ = 0
  • BrickletThermocouple::FILTER_OPTION_60HZ = 1
array BrickletThermocouple::getConfiguration()
Return Array:
  • 'averaging' – Type: int, Range: See constants
  • 'thermocouple_type' – Type: int, Range: See constants
  • 'filter' – Type: int, Range: See constants

Returns the configuration as set by setConfiguration().

The following constants are available for this function:

For $averaging:

  • BrickletThermocouple::AVERAGING_1 = 1
  • BrickletThermocouple::AVERAGING_2 = 2
  • BrickletThermocouple::AVERAGING_4 = 4
  • BrickletThermocouple::AVERAGING_8 = 8
  • BrickletThermocouple::AVERAGING_16 = 16

For $thermocouple_type:

  • BrickletThermocouple::TYPE_B = 0
  • BrickletThermocouple::TYPE_E = 1
  • BrickletThermocouple::TYPE_J = 2
  • BrickletThermocouple::TYPE_K = 3
  • BrickletThermocouple::TYPE_N = 4
  • BrickletThermocouple::TYPE_R = 5
  • BrickletThermocouple::TYPE_S = 6
  • BrickletThermocouple::TYPE_T = 7
  • BrickletThermocouple::TYPE_G8 = 8
  • BrickletThermocouple::TYPE_G32 = 9

For $filter:

  • BrickletThermocouple::FILTER_OPTION_50HZ = 0
  • BrickletThermocouple::FILTER_OPTION_60HZ = 1
array BrickletThermocouple::getErrorState()
Return Array:
  • 'over_under' – Type: bool
  • 'open_circuit' – Type: bool

Returns the current error state. There are two possible errors:

  • Over/Under Voltage and
  • Open Circuit.

Over/Under Voltage happens for voltages below 0V or above 3.3V. In this case it is very likely that your thermocouple is defective. An Open Circuit error indicates that there is no thermocouple connected.

You can use the CALLBACK_ERROR_STATE callback to automatically get triggered when the error state changes.

array BrickletThermocouple::getAPIVersion()
Returns:
  • $api_version – Type: array(int, ...), Length: 3, Range: [0 to 255]

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.

bool BrickletThermocouple::getResponseExpected(int $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 setResponseExpected(). 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.

The following constants are available for this function:

For $function_id:

  • BrickletThermocouple::FUNCTION_SET_TEMPERATURE_CALLBACK_PERIOD = 2
  • BrickletThermocouple::FUNCTION_SET_TEMPERATURE_CALLBACK_THRESHOLD = 4
  • BrickletThermocouple::FUNCTION_SET_DEBOUNCE_PERIOD = 6
  • BrickletThermocouple::FUNCTION_SET_CONFIGURATION = 10
void BrickletThermocouple::setResponseExpected(int $function_id, bool $response_expected)
Parameters:
  • $function_id – Type: int, Range: See constants
  • $response_expected – Type: bool

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.

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 constants are available for this function:

For $function_id:

  • BrickletThermocouple::FUNCTION_SET_TEMPERATURE_CALLBACK_PERIOD = 2
  • BrickletThermocouple::FUNCTION_SET_TEMPERATURE_CALLBACK_THRESHOLD = 4
  • BrickletThermocouple::FUNCTION_SET_DEBOUNCE_PERIOD = 6
  • BrickletThermocouple::FUNCTION_SET_CONFIGURATION = 10
void BrickletThermocouple::setResponseExpectedAll(bool $response_expected)
Parameters:
  • $response_expected – Type: bool

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

array BrickletThermocouple::getIdentity()
Return Array:
  • 'uid' – Type: string, Length: up to 8
  • 'connected_uid' – Type: string, Length: up to 8
  • 'position' – Type: string
  • 'hardware_version' – Type: array(int, ...), Length: 3, Range: [0 to 255]
  • 'firmware_version' – Type: array(int, ...), Length: 3, 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' or 'd'.

The device identifier numbers can be found here. There is also a constant for the device identifier of this Bricklet.

Callback Configuration Functions

void BrickletThermocouple::registerCallback(int $callback_id, callable $callback, mixed $user_data=NULL)
Parameters:
  • $callback_id – Type: int
  • $callback – Type: callable
  • $user_data – Type: mixed

Registers the given $function with the given $callback_id. The optional $user_data will be passed as the last parameter to the function.

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

void BrickletThermocouple::setTemperatureCallbackPeriod(int $period)
Parameters:
  • $period – Type: int, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0

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.

int BrickletThermocouple::getTemperatureCallbackPeriod()
Returns:
  • $period – Type: int, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0

Returns the period as set by setTemperatureCallbackPeriod().

void BrickletThermocouple::setTemperatureCallbackThreshold(string $option, int $min, int $max)
Parameters:
  • $option – Type: string, Range: See constants, Default: 'x'
  • $min – Type: int, Range: [-231 to 231 - 1]
  • $max – Type: int, Range: [-231 to 231 - 1]

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:

For $option:

  • BrickletThermocouple::THRESHOLD_OPTION_OFF = 'x'
  • BrickletThermocouple::THRESHOLD_OPTION_OUTSIDE = 'o'
  • BrickletThermocouple::THRESHOLD_OPTION_INSIDE = 'i'
  • BrickletThermocouple::THRESHOLD_OPTION_SMALLER = '<'
  • BrickletThermocouple::THRESHOLD_OPTION_GREATER = '>'
array BrickletThermocouple::getTemperatureCallbackThreshold()
Return Array:
  • 'option' – Type: string, Range: See constants, Default: 'x'
  • 'min' – Type: int, Range: [-231 to 231 - 1]
  • 'max' – Type: int, Range: [-231 to 231 - 1]

Returns the threshold as set by setTemperatureCallbackThreshold().

The following constants are available for this function:

For $option:

  • BrickletThermocouple::THRESHOLD_OPTION_OFF = 'x'
  • BrickletThermocouple::THRESHOLD_OPTION_OUTSIDE = 'o'
  • BrickletThermocouple::THRESHOLD_OPTION_INSIDE = 'i'
  • BrickletThermocouple::THRESHOLD_OPTION_SMALLER = '<'
  • BrickletThermocouple::THRESHOLD_OPTION_GREATER = '>'
void BrickletThermocouple::setDebouncePeriod(int $debounce)
Parameters:
  • $debounce – Type: int, Unit: 1 ms, Range: [0 to 232 - 1], Default: 100

Sets the period with which the threshold callback

is triggered, if the threshold

keeps being reached.

int BrickletThermocouple::getDebouncePeriod()
Returns:
  • $debounce – Type: int, Unit: 1 ms, Range: [0 to 232 - 1], Default: 100

Returns the debounce period as set by setDebouncePeriod().

Callbacks

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

<?php

function myCallback($param)
{
    echo $param . "\n";
}

$thermocouple->registerCallback(BrickletThermocouple::CALLBACK_EXAMPLE, 'myCallback');

?>

The available constants with corresponding function signatures 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.

int BrickletThermocouple::CALLBACK_TEMPERATURE
<?php   void callback(int $temperature [, mixed $user_data])   ?>
Callback Parameters:
  • $temperature – Type: int, Range: [-231 to 231 - 1]
  • $user_data – Type: mixed

This callback is triggered periodically with the period that is set by setTemperatureCallbackPeriod(). The parameter is the temperature of the thermocouple.

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

int BrickletThermocouple::CALLBACK_TEMPERATURE_REACHED
<?php   void callback(int $temperature [, mixed $user_data])   ?>
Callback Parameters:
  • $temperature – Type: int, Range: [-231 to 231 - 1]
  • $user_data – Type: mixed

This callback is triggered when the threshold as set by setTemperatureCallbackThreshold() is reached. The parameter is the temperature of the thermocouple.

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

int BrickletThermocouple::CALLBACK_ERROR_STATE
<?php   void callback(bool $over_under, bool $open_circuit [, mixed $user_data])   ?>
Callback Parameters:
  • $over_under – Type: bool
  • $open_circuit – Type: bool
  • $user_data – Type: mixed

This Callback is triggered every time the error state changes (see getErrorState()).

Constants

int BrickletThermocouple::DEVICE_IDENTIFIER

This constant is used to identify a Thermocouple Bricklet.

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

string BrickletThermocouple::DEVICE_DISPLAY_NAME

This constant represents the human readable name of a Thermocouple Bricklet.