Perl - Voltage/Current Bricklet

This is the description of the Perl 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 Perl API bindings is part of their general description.

Examples

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

Simple

Download (example_simple.pl)

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#!/usr/bin/perl

use strict;
use Tinkerforge::IPConnection;
use Tinkerforge::BrickletVoltageCurrent;

use constant HOST => 'localhost';
use constant PORT => 4223;
use constant UID => 'XYZ'; # Change XYZ to the UID of your Voltage/Current Bricklet

my $ipcon = Tinkerforge::IPConnection->new(); # Create IP connection
my $vc = Tinkerforge::BrickletVoltageCurrent->new(&UID, $ipcon); # Create device object

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

# Get current voltage
my $voltage = $vc->get_voltage();
print "Voltage: " . $voltage/1000.0 . " V\n";

# Get current current
my $current = $vc->get_current();
print "Current: " . $current/1000.0 . " A\n";

print "Press key to exit\n";
<STDIN>;
$ipcon->disconnect();

Callback

Download (example_callback.pl)

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#!/usr/bin/perl

use strict;
use Tinkerforge::IPConnection;
use Tinkerforge::BrickletVoltageCurrent;

use constant HOST => 'localhost';
use constant PORT => 4223;
use constant UID => 'XYZ'; # Change XYZ to the UID of your Voltage/Current Bricklet

# Callback subroutine for current callback
sub cb_current
{
    my ($current) = @_;

    print "Current: " . $current/1000.0 . " A\n";
}

my $ipcon = Tinkerforge::IPConnection->new(); # Create IP connection
my $vc = Tinkerforge::BrickletVoltageCurrent->new(&UID, $ipcon); # Create device object

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

# Register current callback to subroutine cb_current
$vc->register_callback($vc->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->set_current_callback_period(1000);

print "Press key to exit\n";
<STDIN>;
$ipcon->disconnect();

Threshold

Download (example_threshold.pl)

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#!/usr/bin/perl

use strict;
use Tinkerforge::IPConnection;
use Tinkerforge::BrickletVoltageCurrent;

use constant HOST => 'localhost';
use constant PORT => 4223;
use constant UID => 'XYZ'; # Change XYZ to the UID of your Voltage/Current Bricklet

# Callback subroutine for power reached callback
sub cb_power_reached
{
    my ($power) = @_;

    print "Power: " . $power/1000.0 . " W\n";
}

my $ipcon = Tinkerforge::IPConnection->new(); # Create IP connection
my $vc = Tinkerforge::BrickletVoltageCurrent->new(&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->set_debounce_period(10000);

# Register power reached callback to subroutine cb_power_reached
$vc->register_callback($vc->CALLBACK_POWER_REACHED, 'cb_power_reached');

# Configure threshold for power "greater than 10 W"
$vc->set_power_callback_threshold('>', 10*1000, 0);

print "Press key to exit\n";
<STDIN>;
$ipcon->disconnect();

API

Generally, every subroutine of the Perl bindings can report an error as Tinkerforge::Error object via croak(). The object has a get_code() and a get_message() subroutine. There are different error code:

  • Error->ALREADY_CONNECTED = 11
  • Error->NOT_CONNECTED = 12
  • Error->CONNECT_FAILED = 13
  • Error->INVALID_FUNCTION_ID = 21
  • Error->TIMEOUT = 31
  • Error->INVALID_PARAMETER = 41
  • Error->FUNCTION_NOT_SUPPORTED = 42
  • Error->UNKNOWN_ERROR = 43

All methods listed below are thread-safe.

Basic Functions

BrickletVoltageCurrent->new($uid, $ipcon)
Parameters:
  • $uid -- string
  • $ipcon -- IPConnection
Return type:

BrickletVoltageCurrent

Creates an object with the unique device ID $uid:

$voltage_current = BrickletVoltageCurrent->new("YOUR_DEVICE_UID", $ipcon);

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

BrickletVoltageCurrent->get_current()
Return type:int

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 set_current_callback_period().

BrickletVoltageCurrent->get_voltage()
Return type:int

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 set_voltage_callback_period().

BrickletVoltageCurrent->get_power()
Return type:int

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 set_power_callback_period().

BrickletVoltageCurrent->set_configuration($averaging, $voltage_conversion_time, $current_conversion_time)
Parameters:
  • $averaging -- int
  • $voltage_conversion_time -- int
  • $current_conversion_time -- int
Return type:

undef

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
BrickletVoltageCurrent->get_configuration()
Return type:[int, int, int]

Returns the configuration as set by set_configuration().

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 contains the elements averaging, voltage_conversion_time and current_conversion_time.

Advanced Functions

BrickletVoltageCurrent->set_calibration($gain_multiplier, $gain_divisor)
Parameters:
  • $gain_multiplier -- int
  • $gain_divisor -- int
Return type:

undef

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.

BrickletVoltageCurrent->get_calibration()
Return type:[int, int]

Returns the calibration as set by set_calibration().

The returned array contains the elements gain_multiplier and gain_divisor.

BrickletVoltageCurrent->get_api_version()
Return type:[int, int, int]

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.

BrickletVoltageCurrent->get_response_expected($function_id)
Parameters:$function_id -- int
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.

BrickletVoltageCurrent->set_response_expected($function_id, $response_expected)
Parameters:
  • $function_id -- int
  • $response_expected -- bool
Return type:

undef

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
BrickletVoltageCurrent->set_response_expected_all($response_expected)
Parameters:$response_expected -- bool
Return type:undef

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

BrickletVoltageCurrent->get_identity()
Return type:[string, string, char, [int, int, int], [int, int, int], int]

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 contains the elements uid, connected_uid, position, hardware_version, firmware_version and device_identifier.

Callback Configuration Functions

BrickletVoltageCurrent->register_callback($id, $callback)
Parameters:
  • $id -- int
  • $callback -- string
Return type:

undef

Registers the given $function name with the given $callback_id.

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

BrickletVoltageCurrent->set_current_callback_period($period)
Parameters:$period -- int
Return type:undef

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.

BrickletVoltageCurrent->get_current_callback_period()
Return type:int

Returns the period as set by set_current_callback_period().

BrickletVoltageCurrent->set_voltage_callback_period($period)
Parameters:$period -- int
Return type:undef

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.

BrickletVoltageCurrent->get_voltage_callback_period()
Return type:int

Returns the period as set by set_voltage_callback_period().

BrickletVoltageCurrent->set_power_callback_period($period)
Parameters:$period -- int
Return type:undef

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.

BrickletVoltageCurrent->get_power_callback_period()
Return type:int

Returns the period as set by get_power_callback_period().

BrickletVoltageCurrent->set_current_callback_threshold($option, $min, $max)
Parameters:
  • $option -- char
  • $min -- int
  • $max -- int
Return type:

undef

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 = '>'
BrickletVoltageCurrent->get_current_callback_threshold()
Return type:[char, int, int]

Returns the threshold as set by set_current_callback_threshold().

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 contains the elements option, min and max.

BrickletVoltageCurrent->set_voltage_callback_threshold($option, $min, $max)
Parameters:
  • $option -- char
  • $min -- int
  • $max -- int
Return type:

undef

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 = '>'
BrickletVoltageCurrent->get_voltage_callback_threshold()
Return type:[char, int, int]

Returns the threshold as set by set_voltage_callback_threshold().

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 contains the elements option, min and max.

BrickletVoltageCurrent->set_power_callback_threshold($option, $min, $max)
Parameters:
  • $option -- char
  • $min -- int
  • $max -- int
Return type:

undef

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 = '>'
BrickletVoltageCurrent->get_power_callback_threshold()
Return type:[char, int, int]

Returns the threshold as set by set_power_callback_threshold().

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 contains the elements option, min and max.

BrickletVoltageCurrent->set_debounce_period($debounce)
Parameters:$debounce -- int
Return type:undef

Sets the period in ms with which the threshold callbacks

are triggered, if the thresholds

keep being reached.

The default value is 100.

BrickletVoltageCurrent->get_debounce_period()
Return type:int

Returns the debounce period as set by set_debounce_period().

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 name:

sub my_callback
{
    print "@_[0]";
}

$voltage_current->register_callback(BrickletVoltageCurrent->CALLBACK_EXAMPLE, 'my_callback')

The callback function will be called from an internal thread of the IP Connection. In contrast to many other programming languages, variables are not automatically shared between threads in Perl. If you want to share a global variable between a callback function and the rest for your program it has to be marked as :shared. See the documentation of the threads::shared Perl module for more details.

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.

BrickletVoltageCurrent->CALLBACK_CURRENT
Parameters:$current -- int

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

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

BrickletVoltageCurrent->CALLBACK_VOLTAGE
Parameters:$voltage -- int

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

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

BrickletVoltageCurrent->CALLBACK_POWER
Parameters:$power -- int

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

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

BrickletVoltageCurrent->CALLBACK_CURRENT_REACHED
Parameters:$current -- int

This callback is triggered when the threshold as set by set_current_callback_threshold() 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 set_debounce_period().

BrickletVoltageCurrent->CALLBACK_VOLTAGE_REACHED
Parameters:$voltage -- int

This callback is triggered when the threshold as set by set_voltage_callback_threshold() 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 set_debounce_period().

BrickletVoltageCurrent->CALLBACK_POWER_REACHED
Parameters:$power -- int

This callback is triggered when the threshold as set by set_power_callback_threshold() 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 set_debounce_period().

Constants

BrickletVoltageCurrent->DEVICE_IDENTIFIER

This constant is used to identify a Voltage/Current 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.

BrickletVoltageCurrent->DEVICE_DISPLAY_NAME

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