Shell - Load Cell Bricklet 2.0¶

Simple¶

Download (example-simple.sh)

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#!/bin/sh
# Connects to localhost:4223 by default, use --host and --port to change this

uid=XYZ # Change XYZ to the UID of your Load Cell Bricklet 2.0

# Get current weight
tinkerforge call load-cell-v2-bricklet $uid get-weight

Callback¶

Download (example-callback.sh)

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#!/bin/sh
# Connects to localhost:4223 by default, use --host and --port to change this

uid=XYZ # Change XYZ to the UID of your Load Cell Bricklet 2.0

# Handle incoming weight callbacks
tinkerforge dispatch load-cell-v2-bricklet $uid weight &

# Set period for weight callback to 1s (1000ms) without a threshold
tinkerforge call load-cell-v2-bricklet $uid set-weight-callback-configuration 1000 false threshold-option-off 0 0

echo "Press key to exit"; read dummy

kill -- -$$ # Stop callback dispatch in background

Threshold¶

Download (example-threshold.sh)

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#!/bin/sh
# Connects to localhost:4223 by default, use --host and --port to change this

uid=XYZ # Change XYZ to the UID of your Load Cell Bricklet 2.0

# Handle incoming weight callbacks
tinkerforge dispatch load-cell-v2-bricklet $uid weight &

# Configure threshold for weight "greater than 200 g"
# with a debounce period of 1s (1000ms)
tinkerforge call load-cell-v2-bricklet $uid set-weight-callback-configuration 1000 false threshold-option-greater 200 0

echo "Press key to exit"; read dummy

kill -- -$$ # Stop callback dispatch in background

Command Structure¶

The common options of the call and dispatch commands are documented here. The specific command structure is shown below.

tinkerforge call load-cell-v2-bricklet [<option>..] <uid> <function> [<argument>..]¶

Parameters:	<uid> – Type: String <function> – Type: String

The call command is used to call a function of the Load Cell Bricklet 2.0. It can take several options:

• --help shows help for the specific call command and exits
• --list-functions shows a list of known functions of the Load Cell Bricklet 2.0 and exits

tinkerforge dispatch load-cell-v2-bricklet [<option>..] <uid> <callback>¶

Parameters:	<uid> – Type: String <callback> – Type: String

The dispatch command is used to dispatch a callback of the Load Cell Bricklet 2.0. It can take several options:

• --help shows help for the specific dispatch command and exits
• --list-callbacks shows a list of known callbacks of the Load Cell Bricklet 2.0 and exits

tinkerforge call load-cell-v2-bricklet <uid> <function> [<option>..] [<argument>..]¶

Parameters:	<uid> – Type: String <function> – Type: String

The <function> to be called can take different options depending of its kind. All functions can take the following options:

• --help shows help for the specific function and exits

Getter functions can take the following options:

• --execute <command> shell command line to execute for each incoming response (see section about output formatting for details)

Setter functions can take the following options:

• --expect-response requests response and waits for it

The --expect-response option for setter functions allows to detect timeouts and other error conditions calls of setters as well. The device will then send a response for this purpose. If this option is not given for a setter function then no response is sent and errors are silently ignored, because they cannot be detected.

tinkerforge dispatch load-cell-v2-bricklet <uid> <callback> [<option>..]¶

Parameters:	<uid> – Type: String <callback> – Type: String

The <callback> to be dispatched can take several options:

• --help shows help for the specific callback and exits
• --execute <command> shell command line to execute for each incoming response (see section about output formatting for details)

Basic Functions¶

tinkerforge call load-cell-v2-bricklet <uid> get-weight¶

Output:	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 weight callback. You can set the callback configuration with set-weight-callback-configuration.

tinkerforge call load-cell-v2-bricklet <uid> set-info-led-config <config>¶

Parameters:	<config> – Type: Int, Range: See symbols, Default: 0
Output:	no output

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

The following symbols are available for this function:

For <config>:

• info-led-config-off = 0
• info-led-config-on = 1
• info-led-config-show-heartbeat = 2

tinkerforge call load-cell-v2-bricklet <uid> get-info-led-config¶

Output:	config – Type: Int, Range: See symbols, Default: 0

Returns the LED configuration as set by set-info-led-config

The following symbols are available for this function:

For config:

• info-led-config-off = 0
• info-led-config-on = 1
• info-led-config-show-heartbeat = 2

tinkerforge call load-cell-v2-bricklet <uid> tare¶

Output:	no output

Sets the currently measured weight as tare weight.

Advanced Functions¶

tinkerforge call load-cell-v2-bricklet <uid> set-moving-average <average>¶

Parameters:	<average> – Type: Int, Range: [1 to 100], Default: 4
Output:	no output

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.

tinkerforge call load-cell-v2-bricklet <uid> get-moving-average¶

Output:	average – Type: Int, Range: [1 to 100], Default: 4

Returns the length moving average as set by set-moving-average.

tinkerforge call load-cell-v2-bricklet <uid> calibrate <weight>¶

Parameters:	<weight> – Type: Int, Unit: 1 g, Range: [0 to 232 - 1]
Output:	no output

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.

tinkerforge call load-cell-v2-bricklet <uid> set-configuration <rate> <gain>¶

Parameters:	<rate> – Type: Int, Range: See symbols, Default: 0 <gain> – Type: Int, Range: See symbols, Default: 0
Output:	no output

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 symbols are available for this function:

For <rate>:

• rate-10hz = 0
• rate-80hz = 1

For <gain>:

• gain-128x = 0
• gain-64x = 1
• gain-32x = 2

tinkerforge call load-cell-v2-bricklet <uid> get-configuration¶

Output:	rate – Type: Int, Range: See symbols, Default: 0 gain – Type: Int, Range: See symbols, Default: 0

Returns the configuration as set by set-configuration.

The following symbols are available for this function:

For rate:

• rate-10hz = 0
• rate-80hz = 1

For gain:

• gain-128x = 0
• gain-64x = 1
• gain-32x = 2

tinkerforge call load-cell-v2-bricklet <uid> get-spitfp-error-count¶

Output:	error-count-ack-checksum – Type: Int, Range: [0 to 232 - 1] error-count-message-checksum – Type: Int, Range: [0 to 232 - 1] error-count-frame – Type: Int, Range: [0 to 232 - 1] 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.

tinkerforge call load-cell-v2-bricklet <uid> set-status-led-config <config>¶

Parameters:	<config> – Type: Int, Range: See symbols, Default: 3
Output:	no output

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 symbols are available for this function:

For <config>:

• status-led-config-off = 0
• status-led-config-on = 1
• status-led-config-show-heartbeat = 2
• status-led-config-show-status = 3

tinkerforge call load-cell-v2-bricklet <uid> get-status-led-config¶

Output:	config – Type: Int, Range: See symbols, Default: 3

Returns the configuration as set by set-status-led-config

The following symbols are available for this function:

For config:

• status-led-config-off = 0
• status-led-config-on = 1
• status-led-config-show-heartbeat = 2
• status-led-config-show-status = 3

tinkerforge call load-cell-v2-bricklet <uid> get-chip-temperature¶

Output:	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.

tinkerforge call load-cell-v2-bricklet <uid> reset¶

Output:	no output

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!

tinkerforge call load-cell-v2-bricklet <uid> get-identity¶

Output:

uid – Type: String, Length: up to 8 connected-uid – Type: String, Length: up to 8 position – Type: Char, Range: [a to h, z] hardware-version – Type: Int Array, 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] firmware-version – Type: Int Array, 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] 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. 

Callback Configuration Functions¶

tinkerforge call load-cell-v2-bricklet <uid> 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: false <option> – Type: Char, Range: See symbols, 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
Output:	no output

The period is the period with which the 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 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 symbols are available for this function:

For <option>:

• threshold-option-off = x
• threshold-option-outside = o
• threshold-option-inside = i
• threshold-option-smaller = <
• threshold-option-greater = >

tinkerforge call load-cell-v2-bricklet <uid> get-weight-callback-configuration¶

Output:	period – Type: Int, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0 value-has-to-change – Type: Bool, Default: false option – Type: Char, Range: See symbols, 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 the callback configuration as set by set-weight-callback-configuration.

The following symbols are available for this function:

For option:

• threshold-option-off = x
• threshold-option-outside = o
• threshold-option-inside = i
• threshold-option-smaller = <
• threshold-option-greater = >

Callbacks¶

Callbacks can be used to receive time critical or recurring data from the device:

tinkerforge dispatch load-cell-v2-bricklet <uid> example

The available callbacks are described below.

tinkerforge dispatch load-cell-v2-bricklet <uid> weight¶

Output:	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.

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.

tinkerforge call load-cell-v2-bricklet <uid> set-bootloader-mode <mode>¶

Parameters:	<mode> – Type: Int, Range: See symbols
Output:	status – Type: Int, Range: See symbols

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 symbols are available for this function:

For <mode>:

• bootloader-mode-bootloader = 0
• bootloader-mode-firmware = 1
• bootloader-mode-bootloader-wait-for-reboot = 2
• bootloader-mode-firmware-wait-for-reboot = 3
• bootloader-mode-firmware-wait-for-erase-and-reboot = 4

For status:

• bootloader-status-ok = 0
• bootloader-status-invalid-mode = 1
• bootloader-status-no-change = 2
• bootloader-status-entry-function-not-present = 3
• bootloader-status-device-identifier-incorrect = 4
• bootloader-status-crc-mismatch = 5

tinkerforge call load-cell-v2-bricklet <uid> get-bootloader-mode¶

Output:	mode – Type: Int, Range: See symbols

Returns the current bootloader mode, see set-bootloader-mode.

The following symbols are available for this function:

For mode:

• bootloader-mode-bootloader = 0
• bootloader-mode-firmware = 1
• bootloader-mode-bootloader-wait-for-reboot = 2
• bootloader-mode-firmware-wait-for-reboot = 3
• bootloader-mode-firmware-wait-for-erase-and-reboot = 4

tinkerforge call load-cell-v2-bricklet <uid> set-write-firmware-pointer <pointer>¶

Parameters:	<pointer> – Type: Int, Unit: 1 B, Range: [0 to 232 - 1]
Output:	no output

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.

tinkerforge call load-cell-v2-bricklet <uid> write-firmware <data>¶

Parameters:	<data> – Type: Int Array, Length: 64, Range: [0 to 255]
Output:	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.

tinkerforge call load-cell-v2-bricklet <uid> write-uid <uid>¶

Parameters:	<uid> – Type: Int, Range: [0 to 232 - 1]
Output:	no output

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.

tinkerforge call load-cell-v2-bricklet <uid> read-uid¶

Output:	uid – Type: Int, Range: [0 to 232 - 1]

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