PHP - Voltage/Current Bricklet

This is the description of the PHP API bindings for the Voltage/Current Bricklet. General information and technical specifications for the Voltage/Current 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/BrickletVoltageCurrent.php');

use Tinkerforge\IPConnection;
use Tinkerforge\BrickletVoltageCurrent;

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

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

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

// Get current voltage
$voltage = $vc->getVoltage();
echo "Voltage: " . $voltage/1000.0 . " V\n";

// Get current current
$current = $vc->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/BrickletVoltageCurrent.php');

use Tinkerforge\IPConnection;
use Tinkerforge\BrickletVoltageCurrent;

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

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

$ipcon = new IPConnection(); // Create IP connection
$vc = new BrickletVoltageCurrent(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
$vc->registerCallback(BrickletVoltageCurrent::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!
$vc->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/BrickletVoltageCurrent.php');

use Tinkerforge\IPConnection;
use Tinkerforge\BrickletVoltageCurrent;

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

// Callback function for power reached callback
function cb_powerReached($power)
{
    echo "Power: " . $power/1000.0 . " W\n";
}

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

// Register power reached callback to function cb_powerReached
$vc->registerCallback(BrickletVoltageCurrent::CALLBACK_POWER_REACHED, 'cb_powerReached');

// Configure threshold for power "greater than 10 W"
$vc->setPowerCallbackThreshold('>', 10*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 BrickletVoltageCurrent(string $uid, IPConnection $ipcon)

Creates an object with the unique device ID $uid:

<?php   $voltage_current = new BrickletVoltageCurrent('YOUR_DEVICE_UID', $ipcon);   ?>

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

int BrickletVoltageCurrent::getCurrent()

Returns the current. The value is in mA and between -20000mA and 20000mA.

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

int BrickletVoltageCurrent::getVoltage()

Returns the voltage. The value is in mV and between 0mV and 36000mV.

If you want to get the voltage periodically, it is recommended to use the CALLBACK_VOLTAGE callback and set the period with setVoltageCallbackPeriod().

int BrickletVoltageCurrent::getPower()

Returns the power. The value is in mW and between 0mV and 720000mW.

If you want to get the power periodically, it is recommended to use the CALLBACK_POWER callback and set the period with setPowerCallbackPeriod().

void BrickletVoltageCurrent::setConfiguration(int $averaging, int $voltage_conversion_time, int $current_conversion_time)

Sets the configuration of the Voltage/Current Bricklet. It is possible to configure number of averages as well as voltage and current conversion time.

Averaging:

Value Number of Averages
0 1
1 4
2 16
3 64
4 128
5 256
6 512
>=7 1024

Voltage/Current conversion:

Value Conversion time
0 140µs
1 204µs
2 332µs
3 588µs
4 1.1ms
5 2.116ms
6 4.156ms
>=7 8.244ms

The default values are 3, 4 and 4 (64, 1.1ms, 1.1ms) for averaging, voltage conversion and current conversion.

The following constants are available for this function:

  • BrickletVoltageCurrent::AVERAGING_1 = 0
  • BrickletVoltageCurrent::AVERAGING_4 = 1
  • BrickletVoltageCurrent::AVERAGING_16 = 2
  • BrickletVoltageCurrent::AVERAGING_64 = 3
  • BrickletVoltageCurrent::AVERAGING_128 = 4
  • BrickletVoltageCurrent::AVERAGING_256 = 5
  • BrickletVoltageCurrent::AVERAGING_512 = 6
  • BrickletVoltageCurrent::AVERAGING_1024 = 7
array BrickletVoltageCurrent::getConfiguration()

Returns the configuration as set by setConfiguration().

The following constants are available for this function:

  • BrickletVoltageCurrent::AVERAGING_1 = 0
  • BrickletVoltageCurrent::AVERAGING_4 = 1
  • BrickletVoltageCurrent::AVERAGING_16 = 2
  • BrickletVoltageCurrent::AVERAGING_64 = 3
  • BrickletVoltageCurrent::AVERAGING_128 = 4
  • BrickletVoltageCurrent::AVERAGING_256 = 5
  • BrickletVoltageCurrent::AVERAGING_512 = 6
  • BrickletVoltageCurrent::AVERAGING_1024 = 7

The returned array has the keys averaging, voltage_conversion_time and current_conversion_time.

Advanced Functions

void BrickletVoltageCurrent::setCalibration(int $gain_multiplier, int $gain_divisor)

Since the shunt resistor that is used to measure the current is not perfectly precise, it needs to be calibrated by a multiplier and divisor if a very precise reading is needed.

For example, if you are expecting a measurement of 1000mA and you are measuring 1023mA, you can calibrate the Voltage/Current Bricklet by setting the multiplier to 1000 and the divisor to 1023.

array BrickletVoltageCurrent::getCalibration()

Returns the calibration as set by setCalibration().

The returned array has the keys gain_multiplier and gain_divisor.

array BrickletVoltageCurrent::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 BrickletVoltageCurrent::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 BrickletVoltageCurrent::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:

  • BrickletVoltageCurrent::FUNCTION_SET_CONFIGURATION = 4
  • BrickletVoltageCurrent::FUNCTION_SET_CALIBRATION = 6
  • BrickletVoltageCurrent::FUNCTION_SET_CURRENT_CALLBACK_PERIOD = 8
  • BrickletVoltageCurrent::FUNCTION_SET_VOLTAGE_CALLBACK_PERIOD = 10
  • BrickletVoltageCurrent::FUNCTION_SET_POWER_CALLBACK_PERIOD = 12
  • BrickletVoltageCurrent::FUNCTION_SET_CURRENT_CALLBACK_THRESHOLD = 14
  • BrickletVoltageCurrent::FUNCTION_SET_VOLTAGE_CALLBACK_THRESHOLD = 16
  • BrickletVoltageCurrent::FUNCTION_SET_POWER_CALLBACK_THRESHOLD = 18
  • BrickletVoltageCurrent::FUNCTION_SET_DEBOUNCE_PERIOD = 20
void BrickletVoltageCurrent::setResponseExpectedAll(bool $response_expected)

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

array BrickletVoltageCurrent::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 BrickletVoltageCurrent::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 BrickletVoltageCurrent::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 BrickletVoltageCurrent::getCurrentCallbackPeriod()

Returns the period as set by setCurrentCallbackPeriod().

void BrickletVoltageCurrent::setVoltageCallbackPeriod(int $period)

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

The CALLBACK_VOLTAGE callback is only triggered if the voltage has changed since the last triggering.

The default value is 0.

int BrickletVoltageCurrent::getVoltageCallbackPeriod()

Returns the period as set by setVoltageCallbackPeriod().

void BrickletVoltageCurrent::setPowerCallbackPeriod(int $period)

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

The CALLBACK_POWER callback is only triggered if the power has changed since the last triggering.

The default value is 0.

int BrickletVoltageCurrent::getPowerCallbackPeriod()

Returns the period as set by getPowerCallbackPeriod().

void BrickletVoltageCurrent::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:

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

Returns the threshold as set by setCurrentCallbackThreshold().

The following constants are available for this function:

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

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

void BrickletVoltageCurrent::setVoltageCallbackThreshold(string $option, int $min, int $max)

Sets the thresholds for the CALLBACK_VOLTAGE_REACHED callback.

The following options are possible:

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

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

The following constants are available for this function:

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

Returns the threshold as set by setVoltageCallbackThreshold().

The following constants are available for this function:

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

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

void BrickletVoltageCurrent::setPowerCallbackThreshold(string $option, int $min, int $max)

Sets the thresholds for the CALLBACK_POWER_REACHED callback.

The following options are possible:

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

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

The following constants are available for this function:

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

Returns the threshold as set by setPowerCallbackThreshold().

The following constants are available for this function:

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

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

void BrickletVoltageCurrent::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 BrickletVoltageCurrent::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";
}

$voltage_current->registerCallback(BrickletVoltageCurrent::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 BrickletVoltageCurrent::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 BrickletVoltageCurrent::CALLBACK_VOLTAGE
<?php   void callback(int $voltage [, mixed $user_data])   ?>

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

The CALLBACK_VOLTAGE callback is only triggered if the voltage has changed since the last triggering.

int BrickletVoltageCurrent::CALLBACK_POWER
<?php   void callback(int $power [, mixed $user_data])   ?>

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

The CALLBACK_POWER callback is only triggered if the power has changed since the last triggering.

int BrickletVoltageCurrent::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 BrickletVoltageCurrent::CALLBACK_VOLTAGE_REACHED
<?php   void callback(int $voltage [, mixed $user_data])   ?>

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

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

int BrickletVoltageCurrent::CALLBACK_POWER_REACHED
<?php   void callback(int $power [, mixed $user_data])   ?>

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

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

Constants

int BrickletVoltageCurrent::DEVICE_IDENTIFIER

This constant is used to identify a Voltage/Current 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 BrickletVoltageCurrent::DEVICE_DISPLAY_NAME

This constant represents the human readable name of a Voltage/Current Bricklet.