class Tinkerforge::BrickletLoadCellV2

Measures weight with a load cell

Constants

CALLBACK_WEIGHT

This callback is triggered periodically according to the configuration set by BrickletLoadCellV2#set_weight_callback_configuration.

The parameter is the same as BrickletLoadCellV2#get_weight.

Public Class Methods

new(uid, ipcon) click to toggle source

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

Calls superclass method
# File lib/tinkerforge/bricklet_load_cell_v2.rb, line 80
def initialize(uid, ipcon)
  super uid, ipcon, DEVICE_IDENTIFIER, DEVICE_DISPLAY_NAME

  @api_version = [2, 0, 0]

  @response_expected[FUNCTION_GET_WEIGHT] = RESPONSE_EXPECTED_ALWAYS_TRUE
  @response_expected[FUNCTION_SET_WEIGHT_CALLBACK_CONFIGURATION] = RESPONSE_EXPECTED_TRUE
  @response_expected[FUNCTION_GET_WEIGHT_CALLBACK_CONFIGURATION] = RESPONSE_EXPECTED_ALWAYS_TRUE
  @response_expected[FUNCTION_SET_MOVING_AVERAGE] = RESPONSE_EXPECTED_FALSE
  @response_expected[FUNCTION_GET_MOVING_AVERAGE] = RESPONSE_EXPECTED_ALWAYS_TRUE
  @response_expected[FUNCTION_SET_INFO_LED_CONFIG] = RESPONSE_EXPECTED_FALSE
  @response_expected[FUNCTION_GET_INFO_LED_CONFIG] = RESPONSE_EXPECTED_ALWAYS_TRUE
  @response_expected[FUNCTION_CALIBRATE] = RESPONSE_EXPECTED_FALSE
  @response_expected[FUNCTION_TARE] = RESPONSE_EXPECTED_FALSE
  @response_expected[FUNCTION_SET_CONFIGURATION] = RESPONSE_EXPECTED_FALSE
  @response_expected[FUNCTION_GET_CONFIGURATION] = RESPONSE_EXPECTED_ALWAYS_TRUE
  @response_expected[FUNCTION_GET_SPITFP_ERROR_COUNT] = RESPONSE_EXPECTED_ALWAYS_TRUE
  @response_expected[FUNCTION_SET_BOOTLOADER_MODE] = RESPONSE_EXPECTED_ALWAYS_TRUE
  @response_expected[FUNCTION_GET_BOOTLOADER_MODE] = RESPONSE_EXPECTED_ALWAYS_TRUE
  @response_expected[FUNCTION_SET_WRITE_FIRMWARE_POINTER] = RESPONSE_EXPECTED_FALSE
  @response_expected[FUNCTION_WRITE_FIRMWARE] = RESPONSE_EXPECTED_ALWAYS_TRUE
  @response_expected[FUNCTION_SET_STATUS_LED_CONFIG] = RESPONSE_EXPECTED_FALSE
  @response_expected[FUNCTION_GET_STATUS_LED_CONFIG] = RESPONSE_EXPECTED_ALWAYS_TRUE
  @response_expected[FUNCTION_GET_CHIP_TEMPERATURE] = RESPONSE_EXPECTED_ALWAYS_TRUE
  @response_expected[FUNCTION_RESET] = RESPONSE_EXPECTED_FALSE
  @response_expected[FUNCTION_WRITE_UID] = RESPONSE_EXPECTED_FALSE
  @response_expected[FUNCTION_READ_UID] = RESPONSE_EXPECTED_ALWAYS_TRUE
  @response_expected[FUNCTION_GET_IDENTITY] = RESPONSE_EXPECTED_ALWAYS_TRUE

  @callback_formats[CALLBACK_WEIGHT] = [12, 'l']

  @ipcon.add_device self
end

Public Instance Methods

calibrate(weight) click to toggle source

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.

# File lib/tinkerforge/bricklet_load_cell_v2.rb, line 207
def calibrate(weight)
  check_validity

  send_request FUNCTION_CALIBRATE, [weight], 'L', 8, ''
end
get_bootloader_mode() click to toggle source

Returns the current bootloader mode, see BrickletLoadCellV2#set_bootloader_mode.

# File lib/tinkerforge/bricklet_load_cell_v2.rb, line 278
def get_bootloader_mode
  check_validity

  send_request FUNCTION_GET_BOOTLOADER_MODE, [], '', 9, 'C'
end
get_chip_temperature() click to toggle source

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.

# File lib/tinkerforge/bricklet_load_cell_v2.rb, line 336
def get_chip_temperature
  check_validity

  send_request FUNCTION_GET_CHIP_TEMPERATURE, [], '', 10, 's'
end
get_configuration() click to toggle source

Returns the configuration as set by BrickletLoadCellV2#set_configuration.

# File lib/tinkerforge/bricklet_load_cell_v2.rb, line 239
def get_configuration
  check_validity

  send_request FUNCTION_GET_CONFIGURATION, [], '', 10, 'C C'
end
get_identity() click to toggle source

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 :ref:`Isolator Bricklet <isolator_bricklet>` is always at position 'z'.

The device identifier numbers can be found :ref:`here <device_identifier>`. |device_identifier_constant|

# File lib/tinkerforge/bricklet_load_cell_v2.rb, line 383
def get_identity
  send_request FUNCTION_GET_IDENTITY, [], '', 33, 'Z8 Z8 k C3 C3 S'
end
get_info_led_config() click to toggle source

Returns the LED configuration as set by BrickletLoadCellV2#set_info_led_config

# File lib/tinkerforge/bricklet_load_cell_v2.rb, line 191
def get_info_led_config
  check_validity

  send_request FUNCTION_GET_INFO_LED_CONFIG, [], '', 9, 'C'
end
get_moving_average() click to toggle source

Returns the length moving average as set by BrickletLoadCellV2#set_moving_average.

# File lib/tinkerforge/bricklet_load_cell_v2.rb, line 176
def get_moving_average
  check_validity

  send_request FUNCTION_GET_MOVING_AVERAGE, [], '', 10, 'S'
end
get_spitfp_error_count() click to toggle source

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.

# File lib/tinkerforge/bricklet_load_cell_v2.rb, line 256
def get_spitfp_error_count
  check_validity

  send_request FUNCTION_GET_SPITFP_ERROR_COUNT, [], '', 24, 'L L L L'
end
get_status_led_config() click to toggle source

Returns the configuration as set by BrickletLoadCellV2#set_status_led_config

# File lib/tinkerforge/bricklet_load_cell_v2.rb, line 324
def get_status_led_config
  check_validity

  send_request FUNCTION_GET_STATUS_LED_CONFIG, [], '', 9, 'C'
end
get_weight() click to toggle source

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 BrickletLoadCellV2#set_weight_callback_configuration.

# File lib/tinkerforge/bricklet_load_cell_v2.rb, line 120
def get_weight
  check_validity

  send_request FUNCTION_GET_WEIGHT, [], '', 12, 'l'
end
get_weight_callback_configuration() click to toggle source

Returns the callback configuration as set by BrickletLoadCellV2#set_weight_callback_configuration.

# File lib/tinkerforge/bricklet_load_cell_v2.rb, line 158
def get_weight_callback_configuration
  check_validity

  send_request FUNCTION_GET_WEIGHT_CALLBACK_CONFIGURATION, [], '', 22, 'L ? k l l'
end
read_uid() click to toggle source

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

# File lib/tinkerforge/bricklet_load_cell_v2.rb, line 367
def read_uid
  check_validity

  send_request FUNCTION_READ_UID, [], '', 12, 'L'
end
register_callback(id, &block) click to toggle source

Registers a callback with ID id to the block block.

# File lib/tinkerforge/bricklet_load_cell_v2.rb, line 388
def register_callback(id, &block)
  callback = block
  @registered_callbacks[id] = callback
end
reset() click to toggle source

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!

# File lib/tinkerforge/bricklet_load_cell_v2.rb, line 348
def reset
  check_validity

  send_request FUNCTION_RESET, [], '', 8, ''
end
set_bootloader_mode(mode) click to toggle source

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.

# File lib/tinkerforge/bricklet_load_cell_v2.rb, line 271
def set_bootloader_mode(mode)
  check_validity

  send_request FUNCTION_SET_BOOTLOADER_MODE, [mode], 'C', 9, 'C'
end
set_configuration(rate, gain) click to toggle source

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 BrickletLoadCellV2#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.

# File lib/tinkerforge/bricklet_load_cell_v2.rb, line 232
def set_configuration(rate, gain)
  check_validity

  send_request FUNCTION_SET_CONFIGURATION, [rate, gain], 'C C', 8, ''
end
set_info_led_config(config) click to toggle source

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

# File lib/tinkerforge/bricklet_load_cell_v2.rb, line 184
def set_info_led_config(config)
  check_validity

  send_request FUNCTION_SET_INFO_LED_CONFIG, [config], 'C', 8, ''
end
set_status_led_config(config) click to toggle source

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.

# File lib/tinkerforge/bricklet_load_cell_v2.rb, line 317
def set_status_led_config(config)
  check_validity

  send_request FUNCTION_SET_STATUS_LED_CONFIG, [config], 'C', 8, ''
end
set_weight_callback_configuration(period, value_has_to_change, option, min, max) click to toggle source

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.

# File lib/tinkerforge/bricklet_load_cell_v2.rb, line 151
def set_weight_callback_configuration(period, value_has_to_change, option, min, max)
  check_validity

  send_request FUNCTION_SET_WEIGHT_CALLBACK_CONFIGURATION, [period, value_has_to_change, option, min, max], 'L ? k l l', 8, ''
end
set_write_firmware_pointer(pointer) click to toggle source

Sets the firmware pointer for BrickletLoadCellV2#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.

# File lib/tinkerforge/bricklet_load_cell_v2.rb, line 290
def set_write_firmware_pointer(pointer)
  check_validity

  send_request FUNCTION_SET_WRITE_FIRMWARE_POINTER, [pointer], 'L', 8, ''
end
tare() click to toggle source

Sets the currently measured weight as tare weight.

# File lib/tinkerforge/bricklet_load_cell_v2.rb, line 214
def tare
  check_validity

  send_request FUNCTION_TARE, [], '', 8, ''
end
write_firmware(data) click to toggle source

Writes 64 Bytes of firmware at the position as written by BrickletLoadCellV2#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.

# File lib/tinkerforge/bricklet_load_cell_v2.rb, line 304
def write_firmware(data)
  check_validity

  send_request FUNCTION_WRITE_FIRMWARE, [data], 'C64', 9, 'C'
end
write_uid(uid) click to toggle source

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.

# File lib/tinkerforge/bricklet_load_cell_v2.rb, line 359
def write_uid(uid)
  check_validity

  send_request FUNCTION_WRITE_UID, [uid], 'L', 8, ''
end