This is the description of the Perl API bindings for the Voltage Bricklet. General information and technical specifications for the Voltage Bricklet are summarized in its hardware description.
An installation guide for the Perl 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 | #!/usr/bin/perl
use strict;
use Tinkerforge::IPConnection;
use Tinkerforge::BrickletVoltage;
use constant HOST => 'localhost';
use constant PORT => 4223;
use constant UID => 'XYZ'; # Change XYZ to the UID of your Voltage Bricklet
my $ipcon = Tinkerforge::IPConnection->new(); # Create IP connection
my $v = Tinkerforge::BrickletVoltage->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 = $v->get_voltage();
print "Voltage: " . $voltage/1000.0 . " V\n";
print "Press key to exit\n";
<STDIN>;
$ipcon->disconnect();
|
Download (example_callback.pl)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 | #!/usr/bin/perl
use strict;
use Tinkerforge::IPConnection;
use Tinkerforge::BrickletVoltage;
use constant HOST => 'localhost';
use constant PORT => 4223;
use constant UID => 'XYZ'; # Change XYZ to the UID of your Voltage Bricklet
# Callback subroutine for voltage callback
sub cb_voltage
{
my ($voltage) = @_;
print "Voltage: " . $voltage/1000.0 . " V\n";
}
my $ipcon = Tinkerforge::IPConnection->new(); # Create IP connection
my $v = Tinkerforge::BrickletVoltage->new(&UID, $ipcon); # Create device object
$ipcon->connect(&HOST, &PORT); # Connect to brickd
# Don't use device before ipcon is connected
# Register voltage callback to subroutine cb_voltage
$v->register_callback($v->CALLBACK_VOLTAGE, 'cb_voltage');
# Set period for voltage callback to 1s (1000ms)
# Note: The voltage callback is only called every second
# if the voltage has changed since the last call!
$v->set_voltage_callback_period(1000);
print "Press key to exit\n";
<STDIN>;
$ipcon->disconnect();
|
Download (example_threshold.pl)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 | #!/usr/bin/perl
use strict;
use Tinkerforge::IPConnection;
use Tinkerforge::BrickletVoltage;
use constant HOST => 'localhost';
use constant PORT => 4223;
use constant UID => 'XYZ'; # Change XYZ to the UID of your Voltage Bricklet
# Callback subroutine for voltage reached callback
sub cb_voltage_reached
{
my ($voltage) = @_;
print "Voltage: " . $voltage/1000.0 . " V\n";
}
my $ipcon = Tinkerforge::IPConnection->new(); # Create IP connection
my $v = Tinkerforge::BrickletVoltage->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)
$v->set_debounce_period(10000);
# Register voltage reached callback to subroutine cb_voltage_reached
$v->register_callback($v->CALLBACK_VOLTAGE_REACHED, 'cb_voltage_reached');
# Configure threshold for voltage "greater than 5 V"
$v->set_voltage_callback_threshold('>', 5*1000, 0);
print "Press key to exit\n";
<STDIN>;
$ipcon->disconnect();
|
Generally, every subroutine of the Perl bindings can report an error as
Tinkerforge::Error
object via croak()
. The object has a
get_code()
and a get_message()
subroutine. There are different
error code:
All functions listed below are thread-safe.
BrickletVoltage
->
new
($uid, $ipcon)¶Parameters: |
|
---|---|
Returns: |
|
Creates an object with the unique device ID $uid
:
$voltage = BrickletVoltage->new("YOUR_DEVICE_UID", $ipcon);
This object can then be used after the IP Connection is connected.
BrickletVoltage
->
get_voltage
()¶Returns: |
|
---|
Returns the voltage of the sensor.
If you want to get the voltage periodically, it is recommended to use the
CALLBACK_VOLTAGE
callback and set the period with
set_voltage_callback_period()
.
BrickletVoltage
->
get_analog_value
()¶Returns: |
|
---|
Returns the value as read by a 12-bit analog-to-digital converter.
Note
The value returned by get_voltage()
is averaged over several samples
to yield less noise, while get_analog_value()
gives back raw
unfiltered analog values. The only reason to use get_analog_value()
is,
if you need the full resolution of the analog-to-digital converter.
If you want the analog value periodically, it is recommended to use the
CALLBACK_ANALOG_VALUE
callback and set the period with
set_analog_value_callback_period()
.
BrickletVoltage
->
get_identity
()¶Return Array: |
|
---|
Returns the UID, the UID where the Bricklet is connected to, the position, the hardware and firmware version as well as the device identifier.
The position can be 'a', 'b', 'c', 'd', 'e', 'f', 'g' or 'h' (Bricklet Port). A Bricklet connected to an Isolator Bricklet is always at position 'z'.
The device identifier numbers can be found here. There is also a constant for the device identifier of this Bricklet.
BrickletVoltage
->
register_callback
($callback_id, $function)¶Parameters: |
|
---|---|
Returns: |
|
Registers the given $function
name with the given $callback_id
.
The available callback IDs with corresponding function signatures are listed below.
BrickletVoltage
->
set_voltage_callback_period
($period)¶Parameters: |
|
---|---|
Returns: |
|
Sets the period 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.
BrickletVoltage
->
get_voltage_callback_period
()¶Returns: |
|
---|
Returns the period as set by set_voltage_callback_period()
.
BrickletVoltage
->
set_analog_value_callback_period
($period)¶Parameters: |
|
---|---|
Returns: |
|
Sets the period with which the CALLBACK_ANALOG_VALUE
callback is triggered
periodically. A value of 0 turns the callback off.
The CALLBACK_ANALOG_VALUE
callback is only triggered if the analog value has
changed since the last triggering.
BrickletVoltage
->
get_analog_value_callback_period
()¶Returns: |
|
---|
Returns the period as set by set_analog_value_callback_period()
.
BrickletVoltage
->
set_voltage_callback_threshold
($option, $min, $max)¶Parameters: |
|
---|---|
Returns: |
|
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 following constants are available for this function:
For $option:
BrickletVoltage
->
get_voltage_callback_threshold
()¶Return Array: |
|
---|
Returns the threshold as set by set_voltage_callback_threshold()
.
The following constants are available for this function:
For $option:
BrickletVoltage
->
set_analog_value_callback_threshold
($option, $min, $max)¶Parameters: |
|
---|---|
Returns: |
|
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 following constants are available for this function:
For $option:
BrickletVoltage
->
get_analog_value_callback_threshold
()¶Return Array: |
|
---|
Returns the threshold as set by set_analog_value_callback_threshold()
.
The following constants are available for this function:
For $option:
BrickletVoltage
->
set_debounce_period
($debounce)¶Parameters: |
|
---|---|
Returns: |
|
Sets the period with which the threshold callbacks
are triggered, if the thresholds
keep being reached.
BrickletVoltage
->
get_debounce_period
()¶Returns: |
|
---|
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 name:
sub my_callback
{
print "@_[0]";
}
$voltage->register_callback(BrickletVoltage->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.
BrickletVoltage
->
CALLBACK_VOLTAGE
¶Callback Parameters: |
|
---|
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.
BrickletVoltage
->
CALLBACK_ANALOG_VALUE
¶Callback Parameters: |
|
---|
This callback is triggered periodically with the period that is set by
set_analog_value_callback_period()
. The parameter is the
analog value of the sensor.
The CALLBACK_ANALOG_VALUE
callback is only triggered if the voltage has changed
since the last triggering.
BrickletVoltage
->
CALLBACK_VOLTAGE_REACHED
¶Callback Parameters: |
|
---|
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()
.
BrickletVoltage
->
CALLBACK_ANALOG_VALUE_REACHED
¶Callback Parameters: |
|
---|
This callback is triggered when the threshold as set by
set_analog_value_callback_threshold()
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 set_debounce_period()
.
Virtual functions don't communicate with the device itself, but operate only on the API bindings device object. They can be called without the corresponding IP Connection object being connected.
BrickletVoltage
->
get_api_version
()¶Return Array: |
|
---|
Returns the version of the API definition 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.
BrickletVoltage
->
get_response_expected
($function_id)¶Parameters: |
|
---|---|
Returns: |
|
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 sent and errors are silently ignored, because they cannot be detected.
The following constants are available for this function:
For $function_id:
BrickletVoltage
->
set_response_expected
($function_id, $response_expected)¶Parameters: |
|
---|---|
Returns: |
|
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 sent and errors are silently ignored, because they cannot be detected.
The following constants are available for this function:
For $function_id:
BrickletVoltage
->
set_response_expected_all
($response_expected)¶Parameters: |
|
---|---|
Returns: |
|
Changes the response expected flag for all setter and callback configuration functions of this device at once.
BrickletVoltage
->
DEVICE_IDENTIFIER
¶This constant is used to identify a Voltage Bricklet.
The get_identity()
function and the
IPConnection->CALLBACK_ENUMERATE
callback of the IP Connection have a device_identifier
parameter to specify
the Brick's or Bricklet's type.
BrickletVoltage
->
DEVICE_DISPLAY_NAME
¶This constant represents the human readable name of a Voltage Bricklet.