Perl - Load Cell Bricklet 2.0¶

Simple¶

Download (example_simple.pl)

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#!/usr/bin/perl

use strict;
use Tinkerforge::IPConnection;
use Tinkerforge::BrickletLoadCellV2;

use constant HOST => 'localhost';
use constant PORT => 4223;
use constant UID => 'XYZ'; # Change XYZ to the UID of your Load Cell Bricklet 2.0

my $ipcon = Tinkerforge::IPConnection->new(); # Create IP connection
my $lc = Tinkerforge::BrickletLoadCellV2->new(&UID, $ipcon); # Create device object

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

# Get current weight
my $weight = $lc->get_weight();
print "Weight: $weight g\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::BrickletLoadCellV2;

use constant HOST => 'localhost';
use constant PORT => 4223;
use constant UID => 'XYZ'; # Change XYZ to the UID of your Load Cell Bricklet 2.0

# Callback subroutine for weight callback
sub cb_weight
{
    my ($weight) = @_;

    print "Weight: $weight g\n";
}

my $ipcon = Tinkerforge::IPConnection->new(); # Create IP connection
my $lc = Tinkerforge::BrickletLoadCellV2->new(&UID, $ipcon); # Create device object

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

# Register weight callback to subroutine cb_weight
$lc->register_callback($lc->CALLBACK_WEIGHT, 'cb_weight');

# Set period for weight callback to 1s (1000ms) without a threshold
$lc->set_weight_callback_configuration(1000, 0, 'x', 0, 0);

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::BrickletLoadCellV2;

use constant HOST => 'localhost';
use constant PORT => 4223;
use constant UID => 'XYZ'; # Change XYZ to the UID of your Load Cell Bricklet 2.0

# Callback subroutine for weight callback
sub cb_weight
{
    my ($weight) = @_;

    print "Weight: $weight g\n";
}

my $ipcon = Tinkerforge::IPConnection->new(); # Create IP connection
my $lc = Tinkerforge::BrickletLoadCellV2->new(&UID, $ipcon); # Create device object

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

# Register weight callback to subroutine cb_weight
$lc->register_callback($lc->CALLBACK_WEIGHT, 'cb_weight');

# Configure threshold for weight "greater than 200 g"
# with a debounce period of 1s (1000ms)
$lc->set_weight_callback_configuration(1000, 0, '>', 200, 0);

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

Basic Functions¶

BrickletLoadCellV2->new($uid, $ipcon)¶

Parameters:	$uid – Type: string $ipcon – Type: IPConnection
Returns:	$load_cell_v2 – Type: BrickletLoadCellV2

Creates an object with the unique device ID $uid:

$load_cell_v2 = BrickletLoadCellV2->new("YOUR_DEVICE_UID", $ipcon);

This object can then be used after the IP Connection is connected.

BrickletLoadCellV2->get_weight()¶

Returns:	$weight – Type: int, Unit: 1 g, Range: [-231 to 231 - 1]

Returns the currently measured weight.

If you want to get the value periodically, it is recommended to use the CALLBACK_WEIGHT callback. You can set the callback configuration with set_weight_callback_configuration().

BrickletLoadCellV2->set_info_led_config($config)¶

Parameters:	$config – Type: int, Range: See constants, Default: 0
Returns:	undef

Configures the info LED to be either turned off, turned on, or blink in heartbeat mode.

The following constants are available for this function:

For $config:

• BrickletLoadCellV2->INFO_LED_CONFIG_OFF = 0
• BrickletLoadCellV2->INFO_LED_CONFIG_ON = 1
• BrickletLoadCellV2->INFO_LED_CONFIG_SHOW_HEARTBEAT = 2

BrickletLoadCellV2->get_info_led_config()¶

Returns:	$config – Type: int, Range: See constants, Default: 0

Returns the LED configuration as set by set_info_led_config()

The following constants are available for this function:

For $config:

• BrickletLoadCellV2->INFO_LED_CONFIG_OFF = 0
• BrickletLoadCellV2->INFO_LED_CONFIG_ON = 1
• BrickletLoadCellV2->INFO_LED_CONFIG_SHOW_HEARTBEAT = 2

BrickletLoadCellV2->tare()¶

Returns:	undef

Sets the currently measured weight as tare weight.

Advanced Functions¶

BrickletLoadCellV2->set_moving_average($average)¶

Parameters:	$average – Type: int, Range: [1 to 100], Default: 4
Returns:	undef

Sets the length of a moving averaging for the weight value.

Setting the length to 1 will turn the averaging off. With less averaging, there is more noise on the data.

BrickletLoadCellV2->get_moving_average()¶

Returns:	$average – Type: int, Range: [1 to 100], Default: 4

Returns the length moving average as set by set_moving_average().

BrickletLoadCellV2->calibrate($weight)¶

Parameters:	$weight – Type: int, Unit: 1 g, Range: [0 to 232 - 1]
Returns:	undef

To calibrate your Load Cell Bricklet 2.0 you have to

• empty the scale and call this function with 0 and
• add a known weight to the scale and call this function with the weight.

The calibration is saved in the flash of the Bricklet and only needs to be done once.

We recommend to use the Brick Viewer for calibration, you don't need to call this function in your source code.

BrickletLoadCellV2->set_configuration($rate, $gain)¶

Parameters:	$rate – Type: int, Range: See constants, Default: 0 $gain – Type: int, Range: See constants, Default: 0
Returns:	undef

The measurement rate and gain are configurable.

The rate can be either 10Hz or 80Hz. A faster rate will produce more noise. It is additionally possible to add a moving average (see set_moving_average()) to the measurements.

The gain can be 128x, 64x or 32x. It represents a measurement range of ±20mV, ±40mV and ±80mV respectively. The Load Cell Bricklet uses an excitation voltage of 5V and most load cells use an output of 2mV/V. That means the voltage range is ±15mV for most load cells (i.e. gain of 128x is best). If you don't know what all of this means you should keep it at 128x, it will most likely be correct.

The following constants are available for this function:

For $rate:

• BrickletLoadCellV2->RATE_10HZ = 0
• BrickletLoadCellV2->RATE_80HZ = 1

For $gain:

• BrickletLoadCellV2->GAIN_128X = 0
• BrickletLoadCellV2->GAIN_64X = 1
• BrickletLoadCellV2->GAIN_32X = 2

BrickletLoadCellV2->get_configuration()¶

Return Array:	0: $rate – Type: int, Range: See constants, Default: 0 1: $gain – Type: int, Range: See constants, Default: 0

Returns the configuration as set by set_configuration().

The following constants are available for this function:

For $rate:

• BrickletLoadCellV2->RATE_10HZ = 0
• BrickletLoadCellV2->RATE_80HZ = 1

For $gain:

• BrickletLoadCellV2->GAIN_128X = 0
• BrickletLoadCellV2->GAIN_64X = 1
• BrickletLoadCellV2->GAIN_32X = 2

BrickletLoadCellV2->get_spitfp_error_count()¶

Return Array:	0: $error_count_ack_checksum – Type: int, Range: [0 to 232 - 1] 1: $error_count_message_checksum – Type: int, Range: [0 to 232 - 1] 2: $error_count_frame – Type: int, Range: [0 to 232 - 1] 3: $error_count_overflow – Type: int, Range: [0 to 232 - 1]

Returns the error count for the communication between Brick and Bricklet.

The errors are divided into

• ACK checksum errors,
• message checksum errors,
• framing errors and
• overflow errors.

The errors counts are for errors that occur on the Bricklet side. All Bricks have a similar function that returns the errors on the Brick side.

BrickletLoadCellV2->set_status_led_config($config)¶

Parameters:	$config – Type: int, Range: See constants, Default: 3
Returns:	undef

Sets the status LED configuration. By default the LED shows communication traffic between Brick and Bricklet, it flickers once for every 10 received data packets.

You can also turn the LED permanently on/off or show a heartbeat.

If the Bricklet is in bootloader mode, the LED is will show heartbeat by default.

The following constants are available for this function:

For $config:

• BrickletLoadCellV2->STATUS_LED_CONFIG_OFF = 0
• BrickletLoadCellV2->STATUS_LED_CONFIG_ON = 1
• BrickletLoadCellV2->STATUS_LED_CONFIG_SHOW_HEARTBEAT = 2
• BrickletLoadCellV2->STATUS_LED_CONFIG_SHOW_STATUS = 3

BrickletLoadCellV2->get_status_led_config()¶

Returns:	$config – Type: int, Range: See constants, Default: 3

Returns the configuration as set by set_status_led_config()

The following constants are available for this function:

For $config:

• BrickletLoadCellV2->STATUS_LED_CONFIG_OFF = 0
• BrickletLoadCellV2->STATUS_LED_CONFIG_ON = 1
• BrickletLoadCellV2->STATUS_LED_CONFIG_SHOW_HEARTBEAT = 2
• BrickletLoadCellV2->STATUS_LED_CONFIG_SHOW_STATUS = 3

BrickletLoadCellV2->get_chip_temperature()¶

Returns:	$temperature – Type: int, Unit: 1 °C, Range: [-215 to 215 - 1]

Returns the temperature as measured inside the microcontroller. The value returned is not the ambient temperature!

The temperature is only proportional to the real temperature and it has bad accuracy. Practically it is only useful as an indicator for temperature changes.

BrickletLoadCellV2->reset()¶

Returns:	undef

Calling this function will reset the Bricklet. All configurations will be lost.

After a reset you have to create new device objects, calling functions on the existing ones will result in undefined behavior!

BrickletLoadCellV2->get_identity()¶

Return Array:

0: $uid – Type: string, Length: up to 8 1: $connected_uid – Type: string, Length: up to 8 2: $position – Type: char, Range: ['a' to 'h', 'z'] 3: \@hardware_version – Type: [int, ...], Length: 3 0: $major – Type: int, Range: [0 to 255] 1: $minor – Type: int, Range: [0 to 255] 2: $revision – Type: int, Range: [0 to 255] 4: \@firmware_version – Type: [int, ...], Length: 3 0: $major – Type: int, Range: [0 to 255] 1: $minor – Type: int, Range: [0 to 255] 2: $revision – Type: int, Range: [0 to 255] 5: $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', '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.

Callback Configuration Functions¶

BrickletLoadCellV2->register_callback($callback_id, $function)¶

Parameters:	$callback_id – Type: int $function – Type: string
Returns:	undef

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

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

BrickletLoadCellV2->set_weight_callback_configuration($period, $value_has_to_change, $option, $min, $max)¶

Parameters:	$period – Type: int, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0 $value_has_to_change – Type: bool, Default: 0 $option – Type: char, Range: See constants, Default: 'x' $min – Type: int, Unit: 1 g, Range: [-231 to 231 - 1], Default: 0 $max – Type: int, Unit: 1 g, Range: [-231 to 231 - 1], Default: 0
Returns:	undef

The period is the period with which the CALLBACK_WEIGHT callback is triggered periodically. A value of 0 turns the callback off.

If the value has to change-parameter is set to true, the callback is only triggered after the value has changed. If the value didn't change within the period, the callback is triggered immediately on change.

If it is set to false, the callback is continuously triggered with the period, independent of the value.

It is furthermore possible to constrain the callback with thresholds.

The option-parameter together with min/max sets a threshold for the CALLBACK_WEIGHT callback.

The following options are possible:

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

If the option is set to 'x' (threshold turned off) the callback is triggered with the fixed period.

The following constants are available for this function:

For $option:

• BrickletLoadCellV2->THRESHOLD_OPTION_OFF = 'x'
• BrickletLoadCellV2->THRESHOLD_OPTION_OUTSIDE = 'o'
• BrickletLoadCellV2->THRESHOLD_OPTION_INSIDE = 'i'
• BrickletLoadCellV2->THRESHOLD_OPTION_SMALLER = '<'
• BrickletLoadCellV2->THRESHOLD_OPTION_GREATER = '>'

BrickletLoadCellV2->get_weight_callback_configuration()¶

Return Array:	0: $period – Type: int, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0 1: $value_has_to_change – Type: bool, Default: 0 2: $option – Type: char, Range: See constants, Default: 'x' 3: $min – Type: int, Unit: 1 g, Range: [-231 to 231 - 1], Default: 0 4: $max – Type: int, Unit: 1 g, Range: [-231 to 231 - 1], Default: 0

Returns the callback configuration as set by set_weight_callback_configuration().

The following constants are available for this function:

For $option:

• BrickletLoadCellV2->THRESHOLD_OPTION_OFF = 'x'
• BrickletLoadCellV2->THRESHOLD_OPTION_OUTSIDE = 'o'
• BrickletLoadCellV2->THRESHOLD_OPTION_INSIDE = 'i'
• BrickletLoadCellV2->THRESHOLD_OPTION_SMALLER = '<'
• BrickletLoadCellV2->THRESHOLD_OPTION_GREATER = '>'

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]";
}

$load_cell_v2->register_callback(BrickletLoadCellV2->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.

BrickletLoadCellV2->CALLBACK_WEIGHT¶

Callback Parameters:	$weight – Type: int, Unit: 1 g, Range: [-231 to 231 - 1]

This callback is triggered periodically according to the configuration set by set_weight_callback_configuration().

The parameter is the same as get_weight().

Virtual Functions¶

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.

BrickletLoadCellV2->get_api_version()¶

Return Array:	0: \@api_version – Type: [int, ...], Length: 3 0: $major – Type: int, Range: [0 to 255] 1: $minor – Type: int, Range: [0 to 255] 2: $revision – Type: int, Range: [0 to 255]

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.

BrickletLoadCellV2->get_response_expected($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 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:

• BrickletLoadCellV2->FUNCTION_SET_WEIGHT_CALLBACK_CONFIGURATION = 2
• BrickletLoadCellV2->FUNCTION_SET_MOVING_AVERAGE = 5
• BrickletLoadCellV2->FUNCTION_SET_INFO_LED_CONFIG = 7
• BrickletLoadCellV2->FUNCTION_CALIBRATE = 9
• BrickletLoadCellV2->FUNCTION_TARE = 10
• BrickletLoadCellV2->FUNCTION_SET_CONFIGURATION = 11
• BrickletLoadCellV2->FUNCTION_SET_WRITE_FIRMWARE_POINTER = 237
• BrickletLoadCellV2->FUNCTION_SET_STATUS_LED_CONFIG = 239
• BrickletLoadCellV2->FUNCTION_RESET = 243
• BrickletLoadCellV2->FUNCTION_WRITE_UID = 248

BrickletLoadCellV2->set_response_expected($function_id, $response_expected)¶

Parameters:	$function_id – Type: int, Range: See constants $response_expected – Type: bool
Returns:	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 sent and errors are silently ignored, because they cannot be detected.

The following constants are available for this function:

For $function_id:

• BrickletLoadCellV2->FUNCTION_SET_WEIGHT_CALLBACK_CONFIGURATION = 2
• BrickletLoadCellV2->FUNCTION_SET_MOVING_AVERAGE = 5
• BrickletLoadCellV2->FUNCTION_SET_INFO_LED_CONFIG = 7
• BrickletLoadCellV2->FUNCTION_CALIBRATE = 9
• BrickletLoadCellV2->FUNCTION_TARE = 10
• BrickletLoadCellV2->FUNCTION_SET_CONFIGURATION = 11
• BrickletLoadCellV2->FUNCTION_SET_WRITE_FIRMWARE_POINTER = 237
• BrickletLoadCellV2->FUNCTION_SET_STATUS_LED_CONFIG = 239
• BrickletLoadCellV2->FUNCTION_RESET = 243
• BrickletLoadCellV2->FUNCTION_WRITE_UID = 248

BrickletLoadCellV2->set_response_expected_all($response_expected)¶

Parameters:	$response_expected – Type: bool
Returns:	undef

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

Internal Functions¶

Internal functions are used for maintenance tasks such as flashing a new firmware of changing the UID of a Bricklet. These task should be performed using Brick Viewer instead of using the internal functions directly.

BrickletLoadCellV2->set_bootloader_mode($mode)¶

Parameters:	$mode – Type: int, Range: See constants
Returns:	$status – Type: int, Range: See constants

Sets the bootloader mode and returns the status after the requested mode change was instigated.

You can change from bootloader mode to firmware mode and vice versa. A change from bootloader mode to firmware mode will only take place if the entry function, device identifier and CRC are present and correct.

This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.

The following constants are available for this function:

For $mode:

• BrickletLoadCellV2->BOOTLOADER_MODE_BOOTLOADER = 0
• BrickletLoadCellV2->BOOTLOADER_MODE_FIRMWARE = 1
• BrickletLoadCellV2->BOOTLOADER_MODE_BOOTLOADER_WAIT_FOR_REBOOT = 2
• BrickletLoadCellV2->BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_REBOOT = 3
• BrickletLoadCellV2->BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_ERASE_AND_REBOOT = 4

For $status:

• BrickletLoadCellV2->BOOTLOADER_STATUS_OK = 0
• BrickletLoadCellV2->BOOTLOADER_STATUS_INVALID_MODE = 1
• BrickletLoadCellV2->BOOTLOADER_STATUS_NO_CHANGE = 2
• BrickletLoadCellV2->BOOTLOADER_STATUS_ENTRY_FUNCTION_NOT_PRESENT = 3
• BrickletLoadCellV2->BOOTLOADER_STATUS_DEVICE_IDENTIFIER_INCORRECT = 4
• BrickletLoadCellV2->BOOTLOADER_STATUS_CRC_MISMATCH = 5

BrickletLoadCellV2->get_bootloader_mode()¶

Returns:	$mode – Type: int, Range: See constants

Returns the current bootloader mode, see set_bootloader_mode().

The following constants are available for this function:

For $mode:

• BrickletLoadCellV2->BOOTLOADER_MODE_BOOTLOADER = 0
• BrickletLoadCellV2->BOOTLOADER_MODE_FIRMWARE = 1
• BrickletLoadCellV2->BOOTLOADER_MODE_BOOTLOADER_WAIT_FOR_REBOOT = 2
• BrickletLoadCellV2->BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_REBOOT = 3
• BrickletLoadCellV2->BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_ERASE_AND_REBOOT = 4

BrickletLoadCellV2->set_write_firmware_pointer($pointer)¶

Parameters:	$pointer – Type: int, Unit: 1 B, Range: [0 to 232 - 1]
Returns:	undef

Sets the firmware pointer for write_firmware(). The pointer has to be increased by chunks of size 64. The data is written to flash every 4 chunks (which equals to one page of size 256).

This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.

BrickletLoadCellV2->write_firmware(\@data)¶

Parameters:	\@data – Type: [int, ...], Length: 64, Range: [0 to 255]
Returns:	$status – Type: int, Range: [0 to 255]

Writes 64 Bytes of firmware at the position as written by set_write_firmware_pointer() before. The firmware is written to flash every 4 chunks.

You can only write firmware in bootloader mode.

This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.

BrickletLoadCellV2->write_uid($uid)¶

Parameters:	$uid – Type: int, Range: [0 to 232 - 1]
Returns:	undef

Writes a new UID into flash. If you want to set a new UID you have to decode the Base58 encoded UID string into an integer first.

We recommend that you use Brick Viewer to change the UID.

BrickletLoadCellV2->read_uid()¶

Returns:	$uid – Type: int, Range: [0 to 232 - 1]

Returns the current UID as an integer. Encode as Base58 to get the usual string version.

Constants¶

BrickletLoadCellV2->DEVICE_IDENTIFIER¶

This constant is used to identify a Load Cell Bricklet 2.0.

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.

BrickletLoadCellV2->DEVICE_DISPLAY_NAME¶

This constant represents the human readable name of a Load Cell Bricklet 2.0.