C# - Load Cell Bricklet 2.0

This is the description of the C# API bindings for the Load Cell Bricklet 2.0. General information and technical specifications for the Load Cell Bricklet 2.0 are summarized in its hardware description.

An installation guide for the C# API bindings is part of their general description.

Examples

The example code below is Public Domain (CC0 1.0).

Simple

Download (ExampleSimple.cs)

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using System;
using Tinkerforge;

class Example
{
    private static string HOST = "localhost";
    private static int PORT = 4223;
    private static string UID = "XYZ"; // Change XYZ to the UID of your Load Cell Bricklet 2.0

    static void Main()
    {
        IPConnection ipcon = new IPConnection(); // Create IP connection
        BrickletLoadCellV2 lc = new BrickletLoadCellV2(UID, ipcon); // Create device object

        ipcon.Connect(HOST, PORT); // Connect to brickd
        // Don't use device before ipcon is connected

        // Get current weight
        int weight = lc.GetWeight();
        Console.WriteLine("Weight: " + weight + " g");

        Console.WriteLine("Press enter to exit");
        Console.ReadLine();
        ipcon.Disconnect();
    }
}

Callback

Download (ExampleCallback.cs)

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using System;
using Tinkerforge;

class Example
{
    private static string HOST = "localhost";
    private static int PORT = 4223;
    private static string UID = "XYZ"; // Change XYZ to the UID of your Load Cell Bricklet 2.0

    // Callback function for weight callback
    static void WeightCB(BrickletLoadCellV2 sender, int weight)
    {
        Console.WriteLine("Weight: " + weight + " g");
    }

    static void Main()
    {
        IPConnection ipcon = new IPConnection(); // Create IP connection
        BrickletLoadCellV2 lc = new BrickletLoadCellV2(UID, ipcon); // Create device object

        ipcon.Connect(HOST, PORT); // Connect to brickd
        // Don't use device before ipcon is connected

        // Register weight callback to function WeightCB
        lc.WeightCallback += WeightCB;

        // Set period for weight callback to 1s (1000ms) without a threshold
        lc.SetWeightCallbackConfiguration(1000, false, 'x', 0, 0);

        Console.WriteLine("Press enter to exit");
        Console.ReadLine();
        ipcon.Disconnect();
    }
}

Threshold

Download (ExampleThreshold.cs)

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using System;
using Tinkerforge;

class Example
{
    private static string HOST = "localhost";
    private static int PORT = 4223;
    private static string UID = "XYZ"; // Change XYZ to the UID of your Load Cell Bricklet 2.0

    // Callback function for weight callback
    static void WeightCB(BrickletLoadCellV2 sender, int weight)
    {
        Console.WriteLine("Weight: " + weight + " g");
    }

    static void Main()
    {
        IPConnection ipcon = new IPConnection(); // Create IP connection
        BrickletLoadCellV2 lc = new BrickletLoadCellV2(UID, ipcon); // Create device object

        ipcon.Connect(HOST, PORT); // Connect to brickd
        // Don't use device before ipcon is connected

        // Register weight callback to function WeightCB
        lc.WeightCallback += WeightCB;

        // Configure threshold for weight "greater than 200 g"
        // with a debounce period of 1s (1000ms)
        lc.SetWeightCallbackConfiguration(1000, false, '>', 200, 0);

        Console.WriteLine("Press enter to exit");
        Console.ReadLine();
        ipcon.Disconnect();
    }
}

API

Generally, every method of the C# bindings that returns a value can throw a Tinkerforge.TimeoutException. This exception gets thrown if the device did not respond. If a cable based connection is used, it is unlikely that this exception gets thrown (assuming nobody plugs the device out). However, if a wireless connection is used, timeouts will occur if the distance to the device gets too big.

Since C# does not support multiple return values directly, we use the out keyword to return multiple values from a method.

The namespace for all Brick/Bricklet bindings and the IPConnection is Tinkerforge.*.

All methods listed below are thread-safe.

Basic Functions

public class BrickletLoadCellV2(String uid, IPConnection ipcon)

Creates an object with the unique device ID uid:

BrickletLoadCellV2 loadCellV2 = new BrickletLoadCellV2("YOUR_DEVICE_UID", ipcon);

This object can then be used after the IP Connection is connected (see examples above).

public int GetWeight()

Returns the currently measured weight in grams.

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

public void SetInfoLEDConfig(byte config)

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

The following constants are available for this function:

  • BrickletLoadCellV2.INFO_LED_CONFIG_OFF = 0
  • BrickletLoadCellV2.INFO_LED_CONFIG_ON = 1
  • BrickletLoadCellV2.INFO_LED_CONFIG_SHOW_HEARTBEAT = 2
public byte GetInfoLEDConfig()

Returns the LED configuration as set by SetInfoLEDConfig()

The following constants are available for this function:

  • BrickletLoadCellV2.INFO_LED_CONFIG_OFF = 0
  • BrickletLoadCellV2.INFO_LED_CONFIG_ON = 1
  • BrickletLoadCellV2.INFO_LED_CONFIG_SHOW_HEARTBEAT = 2
public void Tare()

Sets the currently measured weight as tare weight.

Advanced Functions

public void SetMovingAverage(int average)

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.

The range for the averaging is 1-100.

The default value is 4.

public int GetMovingAverage()

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

public void Calibrate(long weight)

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.

public void SetConfiguration(byte rate, byte gain)

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 SetMovingAverage()) 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.

The following constants are available for this function:

  • BrickletLoadCellV2.RATE_10HZ = 0
  • BrickletLoadCellV2.RATE_80HZ = 1
  • BrickletLoadCellV2.GAIN_128X = 0
  • BrickletLoadCellV2.GAIN_64X = 1
  • BrickletLoadCellV2.GAIN_32X = 2
public void GetConfiguration(out byte rate, out byte gain)

Returns the configuration as set by SetConfiguration().

The following constants are available for this function:

  • BrickletLoadCellV2.RATE_10HZ = 0
  • BrickletLoadCellV2.RATE_80HZ = 1
  • BrickletLoadCellV2.GAIN_128X = 0
  • BrickletLoadCellV2.GAIN_64X = 1
  • BrickletLoadCellV2.GAIN_32X = 2
public byte[] GetAPIVersion()

Returns the version of the API definition (major, minor, revision) 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.

public bool GetResponseExpected(byte functionId)

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 SetResponseExpected(). 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 send and errors are silently ignored, because they cannot be detected.

See SetResponseExpected() for the list of function ID constants available for this function.

public void SetResponseExpected(byte functionId, bool responseExpected)

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 send and errors are silently ignored, because they cannot be detected.

The following function ID constants are available for this function:

  • 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
public void SetResponseExpectedAll(bool responseExpected)

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

public void GetSPITFPErrorCount(out long errorCountAckChecksum, out long errorCountMessageChecksum, out long errorCountFrame, out long errorCountOverflow)

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.

public byte SetBootloaderMode(byte 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.

The following constants are available for this function:

  • 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.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
public byte GetBootloaderMode()

Returns the current bootloader mode, see SetBootloaderMode().

The following constants are available for this function:

  • 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
public void SetWriteFirmwarePointer(long pointer)

Sets the firmware pointer for WriteFirmware(). 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.

public byte WriteFirmware(byte[] data)

Writes 64 Bytes of firmware at the position as written by SetWriteFirmwarePointer() 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.

public void SetStatusLEDConfig(byte 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.

The following constants are available for this function:

  • 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
public byte GetStatusLEDConfig()

Returns the configuration as set by SetStatusLEDConfig()

The following constants are available for this function:

  • 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
public short GetChipTemperature()

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.

public void 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!

public void WriteUID(long 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.

public long ReadUID()

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

public void GetIdentity(out string uid, out string connectedUid, out char position, out byte[] hardwareVersion, out byte[] firmwareVersion, out int deviceIdentifier)

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 here. There is also a constant for the device identifier of this Bricklet.

Callback Configuration Functions

public void SetWeightCallbackConfiguration(long period, bool valueHasToChange, char option, int min, int max)

The period in ms is the period with which the WeightCallback 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 WeightCallback 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 default value is (0, false, 'x', 0, 0).

The following constants are available for this function:

  • BrickletLoadCellV2.THRESHOLD_OPTION_OFF = 'x'
  • BrickletLoadCellV2.THRESHOLD_OPTION_OUTSIDE = 'o'
  • BrickletLoadCellV2.THRESHOLD_OPTION_INSIDE = 'i'
  • BrickletLoadCellV2.THRESHOLD_OPTION_SMALLER = '<'
  • BrickletLoadCellV2.THRESHOLD_OPTION_GREATER = '>'
public void GetWeightCallbackConfiguration(out long period, out bool valueHasToChange, out char option, out int min, out int max)

Returns the callback configuration as set by SetWeightCallbackConfiguration().

The following constants are available for this function:

  • 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 by appending your callback handler to the corresponding event:

void MyCallback(BrickletLoadCellV2 sender, int value)
{
    System.Console.WriteLine("Value: " + value);
}

loadCellV2.ExampleCallback += MyCallback;

The available events 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.

public event WeightCallback(BrickletLoadCellV2 sender, int weight)

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

The parameter is the same as GetWeight().

Constants

public int DEVICE_IDENTIFIER

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

The GetIdentity() function and the EnumerateCallback callback of the IP Connection have a deviceIdentifier parameter to specify the Brick's or Bricklet's type.

public string DEVICE_DISPLAY_NAME

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