NAME

Tinkerforge::BrickletLoadCellV2 - Measures weight with a load cell

CONSTANTS

DEVICE_IDENTIFIER

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

The get_identity() subroutine and the CALLBACK_ENUMERATE callback of the IP Connection have a device_identifier parameter to specify the Brick's or Bricklet's type.

DEVICE_DISPLAY_NAME

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

CALLBACK_WEIGHT

This constant is used with the register_callback() subroutine to specify the CALLBACK_WEIGHT callback.

FUNCTION_GET_WEIGHT

This constant is used with the get_response_expected(), set_response_expected() and set_response_expected_all() subroutines.

FUNCTION_SET_WEIGHT_CALLBACK_CONFIGURATION

This constant is used with the get_response_expected(), set_response_expected() and set_response_expected_all() subroutines.

FUNCTION_GET_WEIGHT_CALLBACK_CONFIGURATION

This constant is used with the get_response_expected(), set_response_expected() and set_response_expected_all() subroutines.

FUNCTION_SET_MOVING_AVERAGE

This constant is used with the get_response_expected(), set_response_expected() and set_response_expected_all() subroutines.

FUNCTION_GET_MOVING_AVERAGE

This constant is used with the get_response_expected(), set_response_expected() and set_response_expected_all() subroutines.

FUNCTION_SET_INFO_LED_CONFIG

This constant is used with the get_response_expected(), set_response_expected() and set_response_expected_all() subroutines.

FUNCTION_GET_INFO_LED_CONFIG

This constant is used with the get_response_expected(), set_response_expected() and set_response_expected_all() subroutines.

FUNCTION_CALIBRATE

This constant is used with the get_response_expected(), set_response_expected() and set_response_expected_all() subroutines.

FUNCTION_TARE

This constant is used with the get_response_expected(), set_response_expected() and set_response_expected_all() subroutines.

FUNCTION_SET_CONFIGURATION

This constant is used with the get_response_expected(), set_response_expected() and set_response_expected_all() subroutines.

FUNCTION_GET_CONFIGURATION

This constant is used with the get_response_expected(), set_response_expected() and set_response_expected_all() subroutines.

FUNCTION_GET_SPITFP_ERROR_COUNT

This constant is used with the get_response_expected(), set_response_expected() and set_response_expected_all() subroutines.

FUNCTION_SET_BOOTLOADER_MODE

This constant is used with the get_response_expected(), set_response_expected() and set_response_expected_all() subroutines.

FUNCTION_GET_BOOTLOADER_MODE

This constant is used with the get_response_expected(), set_response_expected() and set_response_expected_all() subroutines.

FUNCTION_SET_WRITE_FIRMWARE_POINTER

This constant is used with the get_response_expected(), set_response_expected() and set_response_expected_all() subroutines.

FUNCTION_WRITE_FIRMWARE

This constant is used with the get_response_expected(), set_response_expected() and set_response_expected_all() subroutines.

FUNCTION_SET_STATUS_LED_CONFIG

This constant is used with the get_response_expected(), set_response_expected() and set_response_expected_all() subroutines.

FUNCTION_GET_STATUS_LED_CONFIG

This constant is used with the get_response_expected(), set_response_expected() and set_response_expected_all() subroutines.

FUNCTION_GET_CHIP_TEMPERATURE

This constant is used with the get_response_expected(), set_response_expected() and set_response_expected_all() subroutines.

FUNCTION_RESET

This constant is used with the get_response_expected(), set_response_expected() and set_response_expected_all() subroutines.

FUNCTION_WRITE_UID

This constant is used with the get_response_expected(), set_response_expected() and set_response_expected_all() subroutines.

FUNCTION_READ_UID

This constant is used with the get_response_expected(), set_response_expected() and set_response_expected_all() subroutines.

FUNCTION_GET_IDENTITY

This constant is used with the get_response_expected(), set_response_expected() and set_response_expected_all() subroutines.

FUNCTIONS

new()

Creates an object with the unique device ID *uid* and adds it to the IP Connection *ipcon*.

get_weight()

Returns the currently measured weight in grams.

If you want to get the value periodically, it is recommended to use the :cb:`Weight` callback. You can set the callback configuration with :func:`Set Weight Callback Configuration`.

set_weight_callback_configuration()

The period in ms is the period with which the :cb:`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 :cb:`Weight` callback.

The following options are possible:

.. csv-table:: :header: "Option", "Description" :widths: 10, 100

"'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 default value is (0, false, 'x', 0, 0).

get_weight_callback_configuration()

Returns the callback configuration as set by :func:`Set Weight Callback Configuration`.

set_moving_average()

Sets the length of a `moving averaging <https://en.wikipedia.org/wiki/Moving_average>`__ for the weight value.

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

The range for the averaging is 1-100.

The default value is 4.

get_moving_average()

Returns the length moving average as set by :func:`Set Moving Average`.

set_info_led_config()

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

get_info_led_config()

Returns the LED configuration as set by :func:`Set Info LED Config`

calibrate()

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 in grams.

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.

tare()

Sets the currently measured weight as tare weight.

set_configuration()

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 :func:`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 default rate is 10Hz and the default gain is 128x.

get_configuration()

Returns the configuration as set by :func:`Set Configuration`.

get_spitfp_error_count()

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.

set_bootloader_mode()

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.

get_bootloader_mode()

Returns the current bootloader mode, see :func:`Set Bootloader Mode`.

set_write_firmware_pointer()

Sets the firmware pointer for :func:`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.

write_firmware()

Writes 64 Bytes of firmware at the position as written by :func:`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.

set_status_led_config()

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.

get_status_led_config()

Returns the configuration as set by :func:`Set Status LED Config`

get_chip_temperature()

Returns the temperature in °C 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.

reset()

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!

write_uid()

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.

read_uid()

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

get_identity()

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 :ref:`here <device_identifier>`. |device_identifier_constant|