PHP - Current12 Bricklet

This is the description of the PHP API bindings for the Current12 Bricklet. General information and technical specifications for the Current12 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)

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<?php

require_once('Tinkerforge/IPConnection.php');
require_once('Tinkerforge/BrickletCurrent12.php');

use Tinkerforge\IPConnection;
use Tinkerforge\BrickletCurrent12;

const HOST = 'localhost';
const PORT = 4223;
const UID = 'XYZ'; // Change XYZ to the UID of your Current12 Bricklet

$ipcon = new IPConnection(); // Create IP connection
$c = new BrickletCurrent12(UID, $ipcon); // Create device object

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

// Get current current
$current = $c->getCurrent();
echo "Current: " . $current/1000.0 . " A\n";

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

?>

Callback

Download (ExampleCallback.php)

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<?php

require_once('Tinkerforge/IPConnection.php');
require_once('Tinkerforge/BrickletCurrent12.php');

use Tinkerforge\IPConnection;
use Tinkerforge\BrickletCurrent12;

const HOST = 'localhost';
const PORT = 4223;
const UID = 'XYZ'; // Change XYZ to the UID of your Current12 Bricklet

// Callback function for current callback
function cb_current($current)
{
    echo "Current: " . $current/1000.0 . " A\n";
}

$ipcon = new IPConnection(); // Create IP connection
$c = new BrickletCurrent12(UID, $ipcon); // Create device object

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

// Register current callback to function cb_current
$c->registerCallback(BrickletCurrent12::CALLBACK_CURRENT, 'cb_current');

// Set period for current callback to 1s (1000ms)
// Note: The current callback is only called every second
//       if the current has changed since the last call!
$c->setCurrentCallbackPeriod(1000);

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

?>

Threshold

Download (ExampleThreshold.php)

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<?php

require_once('Tinkerforge/IPConnection.php');
require_once('Tinkerforge/BrickletCurrent12.php');

use Tinkerforge\IPConnection;
use Tinkerforge\BrickletCurrent12;

const HOST = 'localhost';
const PORT = 4223;
const UID = 'XYZ'; // Change XYZ to the UID of your Current12 Bricklet

// Callback function for current reached callback
function cb_currentReached($current)
{
    echo "Current: " . $current/1000.0 . " A\n";
}

$ipcon = new IPConnection(); // Create IP connection
$c = new BrickletCurrent12(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)
$c->setDebouncePeriod(10000);

// Register current reached callback to function cb_currentReached
$c->registerCallback(BrickletCurrent12::CALLBACK_CURRENT_REACHED, 'cb_currentReached');

// Configure threshold for current "greater than 5 A"
$c->setCurrentCallbackThreshold('>', 5*1000, 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 BrickletCurrent12(string $uid, IPConnection $ipcon)

Creates an object with the unique device ID $uid:

<?php   $current12 = new BrickletCurrent12('YOUR_DEVICE_UID', $ipcon);   ?>

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

int BrickletCurrent12::getCurrent()

Returns the current of the sensor. The value is in mA and between -12500mA and 12500mA.

If you want to get the current periodically, it is recommended to use the CALLBACK_CURRENT callback and set the period with setCurrentCallbackPeriod().

Advanced Functions

void BrickletCurrent12::calibrate()

Calibrates the 0 value of the sensor. You have to call this function when there is no current present.

The zero point of the current sensor is depending on the exact properties of the analog-to-digital converter, the length of the Bricklet cable and the temperature. Thus, if you change the Brick or the environment in which the Bricklet is used, you might have to recalibrate.

The resulting calibration will be saved on the EEPROM of the Current Bricklet.

bool BrickletCurrent12::isOverCurrent()

Returns true if more than 12.5A were measured.

Note

To reset this value you have to power cycle the Bricklet.

int BrickletCurrent12::getAnalogValue()

Returns the value as read by a 12-bit analog-to-digital converter. The value is between 0 and 4095.

Note

The value returned by getCurrent() is averaged over several samples to yield less noise, while getAnalogValue() gives back raw unfiltered analog values. The only reason to use getAnalogValue() is, if you need the full resolution of the analog-to-digital converter.

If you want the analog value periodically, it is recommended to use the CALLBACK_ANALOG_VALUE callback and set the period with setAnalogValueCallbackPeriod().

array BrickletCurrent12::getAPIVersion()

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 BrickletCurrent12::getResponseExpected(int $function_id)

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.

See setResponseExpected() for the list of function ID constants available for this function.

void BrickletCurrent12::setResponseExpected(int $function_id, bool $response_expected)

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 function ID constants are available for this function:

  • BrickletCurrent12::FUNCTION_CALIBRATE = 2
  • BrickletCurrent12::FUNCTION_SET_CURRENT_CALLBACK_PERIOD = 5
  • BrickletCurrent12::FUNCTION_SET_ANALOG_VALUE_CALLBACK_PERIOD = 7
  • BrickletCurrent12::FUNCTION_SET_CURRENT_CALLBACK_THRESHOLD = 9
  • BrickletCurrent12::FUNCTION_SET_ANALOG_VALUE_CALLBACK_THRESHOLD = 11
  • BrickletCurrent12::FUNCTION_SET_DEBOUNCE_PERIOD = 13
void BrickletCurrent12::setResponseExpectedAll(bool $response_expected)

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

array BrickletCurrent12::getIdentity()

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 array has the keys uid, connected_uid, position, hardware_version, firmware_version and device_identifier.

Callback Configuration Functions

void BrickletCurrent12::registerCallback(int $callback_id, callable $callback, mixed $user_data=NULL)

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 BrickletCurrent12::setCurrentCallbackPeriod(int $period)

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

The CALLBACK_CURRENT callback is only triggered if the current has changed since the last triggering.

The default value is 0.

int BrickletCurrent12::getCurrentCallbackPeriod()

Returns the period as set by setCurrentCallbackPeriod().

void BrickletCurrent12::setAnalogValueCallbackPeriod(int $period)

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

The CALLBACK_ANALOG_VALUE callback is only triggered if the analog value has changed since the last triggering.

The default value is 0.

int BrickletCurrent12::getAnalogValueCallbackPeriod()

Returns the period as set by setAnalogValueCallbackPeriod().

void BrickletCurrent12::setCurrentCallbackThreshold(string $option, int $min, int $max)

Sets the thresholds for the CALLBACK_CURRENT_REACHED callback.

The following options are possible:

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

The default value is ('x', 0, 0).

The following constants are available for this function:

  • BrickletCurrent12::THRESHOLD_OPTION_OFF = 'x'
  • BrickletCurrent12::THRESHOLD_OPTION_OUTSIDE = 'o'
  • BrickletCurrent12::THRESHOLD_OPTION_INSIDE = 'i'
  • BrickletCurrent12::THRESHOLD_OPTION_SMALLER = '<'
  • BrickletCurrent12::THRESHOLD_OPTION_GREATER = '>'
array BrickletCurrent12::getCurrentCallbackThreshold()

Returns the threshold as set by setCurrentCallbackThreshold().

The following constants are available for this function:

  • BrickletCurrent12::THRESHOLD_OPTION_OFF = 'x'
  • BrickletCurrent12::THRESHOLD_OPTION_OUTSIDE = 'o'
  • BrickletCurrent12::THRESHOLD_OPTION_INSIDE = 'i'
  • BrickletCurrent12::THRESHOLD_OPTION_SMALLER = '<'
  • BrickletCurrent12::THRESHOLD_OPTION_GREATER = '>'

The returned array has the keys option, min and max.

void BrickletCurrent12::setAnalogValueCallbackThreshold(string $option, int $min, int $max)

Sets the thresholds for the CALLBACK_ANALOG_VALUE_REACHED callback.

The following options are possible:

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

The default value is ('x', 0, 0).

The following constants are available for this function:

  • BrickletCurrent12::THRESHOLD_OPTION_OFF = 'x'
  • BrickletCurrent12::THRESHOLD_OPTION_OUTSIDE = 'o'
  • BrickletCurrent12::THRESHOLD_OPTION_INSIDE = 'i'
  • BrickletCurrent12::THRESHOLD_OPTION_SMALLER = '<'
  • BrickletCurrent12::THRESHOLD_OPTION_GREATER = '>'
array BrickletCurrent12::getAnalogValueCallbackThreshold()

Returns the threshold as set by setAnalogValueCallbackThreshold().

The following constants are available for this function:

  • BrickletCurrent12::THRESHOLD_OPTION_OFF = 'x'
  • BrickletCurrent12::THRESHOLD_OPTION_OUTSIDE = 'o'
  • BrickletCurrent12::THRESHOLD_OPTION_INSIDE = 'i'
  • BrickletCurrent12::THRESHOLD_OPTION_SMALLER = '<'
  • BrickletCurrent12::THRESHOLD_OPTION_GREATER = '>'

The returned array has the keys option, min and max.

void BrickletCurrent12::setDebouncePeriod(int $debounce)

Sets the period in ms with which the threshold callbacks

are triggered, if the thresholds

keep being reached.

The default value is 100.

int BrickletCurrent12::getDebouncePeriod()

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";
}

$current12->registerCallback(BrickletCurrent12::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 BrickletCurrent12::CALLBACK_CURRENT
<?php   void callback(int $current [, mixed $user_data])   ?>

This callback is triggered periodically with the period that is set by setCurrentCallbackPeriod(). The parameter is the current of the sensor.

The CALLBACK_CURRENT callback is only triggered if the current has changed since the last triggering.

int BrickletCurrent12::CALLBACK_ANALOG_VALUE
<?php   void callback(int $value [, mixed $user_data])   ?>

This callback is triggered periodically with the period that is set by setAnalogValueCallbackPeriod(). The parameter is the analog value of the sensor.

The CALLBACK_ANALOG_VALUE callback is only triggered if the current has changed since the last triggering.

int BrickletCurrent12::CALLBACK_CURRENT_REACHED
<?php   void callback(int $current [, mixed $user_data])   ?>

This callback is triggered when the threshold as set by setCurrentCallbackThreshold() is reached. The parameter is the current of the sensor.

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

int BrickletCurrent12::CALLBACK_ANALOG_VALUE_REACHED
<?php   void callback(int $value [, mixed $user_data])   ?>

This callback is triggered when the threshold as set by setAnalogValueCallbackThreshold() is reached. The parameter is the analog value of the sensor.

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

int BrickletCurrent12::CALLBACK_OVER_CURRENT
<?php   void callback([mixed $user_data])   ?>

This callback is triggered when an over current is measured (see isOverCurrent()).

Constants

int BrickletCurrent12::DEVICE_IDENTIFIER

This constant is used to identify a Current12 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 BrickletCurrent12::DEVICE_DISPLAY_NAME

This constant represents the human readable name of a Current12 Bricklet.