Mathematica - Load Cell Bricklet

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

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

Examples

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

Simple

Download (ExampleSimple.nb)

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Needs["NETLink`"]
LoadNETAssembly["Tinkerforge",NotebookDirectory[]<>"../../.."]

host="localhost"
port=4223
uid="XYZ"(*Change XYZ to the UID of your Load Cell Bricklet*)

(*Create IPConnection and device object*)
ipcon=NETNew["Tinkerforge.IPConnection"]
lc=NETNew["Tinkerforge.BrickletLoadCell",uid,ipcon]
ipcon@Connect[host,port]

(*Get current weight*)
Print["Weight: "<>ToString[N[Quantity[lc@GetWeight[],"g"]]]]

(*Clean up*)
ipcon@Disconnect[]
ReleaseNETObject[lc]
ReleaseNETObject[ipcon]

Callback

Download (ExampleCallback.nb)

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Needs["NETLink`"]
LoadNETAssembly["Tinkerforge",NotebookDirectory[]<>"../../.."]

host="localhost"
port=4223
uid="XYZ"(*Change XYZ to the UID of your Load Cell Bricklet*)

(*Create IPConnection and device object*)
ipcon=NETNew["Tinkerforge.IPConnection"]
lc=NETNew["Tinkerforge.BrickletLoadCell",uid,ipcon]
ipcon@Connect[host,port]

(*Callback function for weight callback*)
WeightCB[sender_,weight_]:=
 Print["Weight: "<>ToString[N[Quantity[weight,"g"]]]]
AddEventHandler[lc@WeightCallback,WeightCB]

(*Set period for weight callback to 1s (1000ms)*)
(*Note: The weight callback is only called every second*)
(*if the weight has changed since the last call!*)
lc@SetWeightCallbackPeriod[1000]

Input["Click OK to exit"]

(*Clean up*)
ipcon@Disconnect[]
ReleaseNETObject[lc]
ReleaseNETObject[ipcon]

Threshold

Download (ExampleThreshold.nb)

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Needs["NETLink`"]
LoadNETAssembly["Tinkerforge",NotebookDirectory[]<>"../../.."]

host="localhost"
port=4223
uid="XYZ"(*Change XYZ to the UID of your Load Cell Bricklet*)

(*Create IPConnection and device object*)
ipcon=NETNew["Tinkerforge.IPConnection"]
lc=NETNew["Tinkerforge.BrickletLoadCell",uid,ipcon]
ipcon@Connect[host,port]

(*Get threshold callbacks with a debounce time of 1 second (1000ms)*)
lc@SetDebouncePeriod[1000]

(*Callback function for weight reached callback*)
WeightReachedCB[sender_,weight_]:=
 Print["Weight: "<>ToString[N[Quantity[weight,"g"]]]]
AddEventHandler[lc@WeightReachedCallback,WeightReachedCB]

(*Configure threshold for weight "greater than 200 g"*)
option=Tinkerforge`BrickletLoadCell`THRESHOLDUOPTIONUGREATER
lc@SetWeightCallbackThreshold[option,200,0]

Input["Click OK to exit"]

(*Clean up*)
ipcon@Disconnect[]
ReleaseNETObject[lc]
ReleaseNETObject[ipcon]

API

Generally, every function of the Mathematica 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 .NET/Link does not support multiple return values directly, we use the out keyword to return multiple values from a function. For further information about the out keyword in .NET/Link see the corresponding Mathematica .NET/Link documentation.

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

Basic Functions

BrickletLoadCell[uid, ipcon] → loadCell
Parameters:
  • uid – Type: String
  • ipcon – Type: NETObject[IPConnection]
Returns:
  • loadCell – Type: NETObject[BrickletLoadCell]

Creates an object with the unique device ID uid:

loadCell=NETNew["Tinkerforge.BrickletLoadCell","YOUR_DEVICE_UID",ipcon]

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

The .NET runtime has built-in garbage collection that frees objects that are no longer in use by a program. But because Mathematica can not automatically tell when a Mathematica "program" doesn't use a .NET object anymore, this has to be done by the program. For this the ReleaseNETObject[] function is used in the examples.

For further information about object management in .NET/Link see the corresponding Mathematica .NET/Link documentation.

BrickletLoadCell@GetWeight[] → weight
Returns:
  • weight – Type: Integer, Unit: 1 g, Range: [-231 to 231 - 1]

Returns the currently measured weight.

If you want to get the weight periodically, it is recommended to use the WeightCallback callback and set the period with SetWeightCallbackPeriod[].

BrickletLoadCell@LEDOn[] → Null

Turns the LED on.

BrickletLoadCell@LEDOff[] → Null

Turns the LED off.

BrickletLoadCell@IsLEDOn[] → on
Returns:
  • on – Type: True/False, Default: False

Returns true if the led is on, false otherwise.

BrickletLoadCell@Tare[] → Null

Sets the currently measured weight as tare weight.

Advanced Functions

BrickletLoadCell@SetMovingAverage[average] → Null
Parameters:
  • average – Type: Integer, Range: [1 to 40], Default: 4

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.

BrickletLoadCell@GetMovingAverage[] → average
Returns:
  • average – Type: Integer, Range: [1 to 40], Default: 4

Returns the length moving average as set by SetMovingAverage[].

BrickletLoadCell@Calibrate[weight] → Null
Parameters:
  • weight – Type: Integer, Unit: 1 g, Range: [0 to 232 - 1]

To calibrate your Load Cell Bricklet 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 EEPROM 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.

BrickletLoadCell@SetConfiguration[rate, gain] → Null
Parameters:
  • rate – Type: Integer, Range: See constants, Default: 0
  • gain – Type: Integer, Range: See constants, Default: 0

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 configuration is saved in the EEPROM of the Bricklet and only needs to be done once.

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

The following constants are available for this function:

For rate:

  • BrickletLoadCell`RATEU10HZ = 0
  • BrickletLoadCell`RATEU80HZ = 1

For gain:

  • BrickletLoadCell`GAINU128X = 0
  • BrickletLoadCell`GAINU64X = 1
  • BrickletLoadCell`GAINU32X = 2
BrickletLoadCell@GetConfiguration[out rate, out gain] → Null
Output Parameters:
  • rate – Type: Integer, Range: See constants, Default: 0
  • gain – Type: Integer, Range: See constants, Default: 0

Returns the configuration as set by SetConfiguration[].

The following constants are available for this function:

For rate:

  • BrickletLoadCell`RATEU10HZ = 0
  • BrickletLoadCell`RATEU80HZ = 1

For gain:

  • BrickletLoadCell`GAINU128X = 0
  • BrickletLoadCell`GAINU64X = 1
  • BrickletLoadCell`GAINU32X = 2
BrickletLoadCell@GetIdentity[out uid, out connectedUid, out position, out {hardwareVersion1, hardwareVersion2, hardwareVersion3}, out {firmwareVersion1, firmwareVersion2, firmwareVersion3}, out deviceIdentifier] → Null
Output Parameters:
  • uid – Type: String, Length: up to 8
  • connectedUid – Type: String, Length: up to 8
  • position – Type: Integer, Range: [ToCharacterCode["a"][[0]] to ToCharacterCode["h"][[0]], ToCharacterCode["i"][[0]], ToCharacterCode["z"][[0]]]
  • hardwareVersioni – Type: Integer
    • 1: major – Type: Integer, Range: [0 to 255]
    • 2: minor – Type: Integer, Range: [0 to 255]
    • 3: revision – Type: Integer, Range: [0 to 255]
  • firmwareVersioni – Type: Integer
    • 1: major – Type: Integer, Range: [0 to 255]
    • 2: minor – Type: Integer, Range: [0 to 255]
    • 3: revision – Type: Integer, Range: [0 to 255]
  • deviceIdentifier – Type: Integer, 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). The Raspberry Pi HAT (Zero) Brick is always at position 'i' and the Bricklet connected to an Isolator Bricklet is always as 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

BrickletLoadCell@SetWeightCallbackPeriod[period] → Null
Parameters:
  • period – Type: Integer, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0

Sets the period with which the WeightCallback callback is triggered periodically. A value of 0 turns the callback off.

The WeightCallback callback is only triggered if the weight has changed since the last triggering.

BrickletLoadCell@GetWeightCallbackPeriod[] → period
Returns:
  • period – Type: Integer, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0

Returns the period as set by SetWeightCallbackPeriod[].

BrickletLoadCell@SetWeightCallbackThreshold[option, min, max] → Null
Parameters:
  • option – Type: Integer, Range: See constants, Default: ToCharacterCode["x"][[0]]
  • min – Type: Integer, Unit: 1 g, Range: [-231 to 231 - 1], Default: 0
  • max – Type: Integer, Unit: 1 g, Range: [-231 to 231 - 1], Default: 0

Sets the thresholds for the WeightReachedCallback callback.

The following options are possible:

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

The following constants are available for this function:

For option:

  • BrickletLoadCell`THRESHOLDUOPTIONUOFF = ToCharacterCode["x"][[0]]
  • BrickletLoadCell`THRESHOLDUOPTIONUOUTSIDE = ToCharacterCode["o"][[0]]
  • BrickletLoadCell`THRESHOLDUOPTIONUINSIDE = ToCharacterCode["i"][[0]]
  • BrickletLoadCell`THRESHOLDUOPTIONUSMALLER = ToCharacterCode["<"][[0]]
  • BrickletLoadCell`THRESHOLDUOPTIONUGREATER = ToCharacterCode[">"][[0]]
BrickletLoadCell@GetWeightCallbackThreshold[out option, out min, out max] → Null
Output Parameters:
  • option – Type: Integer, Range: See constants, Default: ToCharacterCode["x"][[0]]
  • min – Type: Integer, Unit: 1 g, Range: [-231 to 231 - 1], Default: 0
  • max – Type: Integer, Unit: 1 g, Range: [-231 to 231 - 1], Default: 0

Returns the threshold as set by SetWeightCallbackThreshold[].

The following constants are available for this function:

For option:

  • BrickletLoadCell`THRESHOLDUOPTIONUOFF = ToCharacterCode["x"][[0]]
  • BrickletLoadCell`THRESHOLDUOPTIONUOUTSIDE = ToCharacterCode["o"][[0]]
  • BrickletLoadCell`THRESHOLDUOPTIONUINSIDE = ToCharacterCode["i"][[0]]
  • BrickletLoadCell`THRESHOLDUOPTIONUSMALLER = ToCharacterCode["<"][[0]]
  • BrickletLoadCell`THRESHOLDUOPTIONUGREATER = ToCharacterCode[">"][[0]]
BrickletLoadCell@SetDebouncePeriod[debounce] → Null
Parameters:
  • debounce – Type: Integer, Unit: 1 ms, Range: [0 to 232 - 1], Default: 100

Sets the period with which the threshold callback

is triggered, if the threshold

keeps being reached.

BrickletLoadCell@GetDebouncePeriod[] → debounce
Returns:
  • debounce – Type: Integer, Unit: 1 ms, Range: [0 to 232 - 1], Default: 100

Returns the debounce period as set by SetDebouncePeriod[].

Callbacks

Callbacks can be registered to receive time critical or recurring data from the device. The registration is done by assigning a function to a callback property of the device object:

MyCallback[sender_,value_]:=Print["Value: "<>ToString[value]]

AddEventHandler[loadCell@ExampleCallback,MyCallback]

For further information about event handling using .NET/Link see the corresponding Mathematica .NET/Link documentation.

The available callback property and their type of parameters 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.

event BrickletLoadCell@WeightCallback[sender, weight]
Callback Parameters:
  • sender – Type: NETObject[BrickletLoadCell]
  • weight – Type: Integer, Unit: 1 g, Range: [-231 to 231 - 1]

This callback is triggered periodically with the period that is set by SetWeightCallbackPeriod[]. The parameter is the weight as measured by the load cell.

The WeightCallback callback is only triggered if the weight has changed since the last triggering.

event BrickletLoadCell@WeightReachedCallback[sender, weight]
Callback Parameters:
  • sender – Type: NETObject[BrickletLoadCell]
  • weight – Type: Integer, Unit: 1 g, Range: [-231 to 231 - 1]

This callback is triggered when the threshold as set by SetWeightCallbackThreshold[] is reached. The parameter is the weight as measured by the load cell.

If the threshold keeps being reached, the callback is triggered periodically with the period as set by SetDebouncePeriod[].

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.

BrickletLoadCell@GetAPIVersion[] → {apiVersion1, apiVersion2, apiVersion3}
Output Parameters:
  • apiVersioni – Type: Integer
    • 1: major – Type: Integer, Range: [0 to 255]
    • 2: minor – Type: Integer, Range: [0 to 255]
    • 3: revision – Type: Integer, 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.

BrickletLoadCell@GetResponseExpected[functionId] → responseExpected
Parameters:
  • functionId – Type: Integer, Range: See constants
Returns:
  • responseExpected – Type: True/False

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

The following constants are available for this function:

For functionId:

  • BrickletLoadCell`FUNCTIONUSETUWEIGHTUCALLBACKUPERIOD = 2
  • BrickletLoadCell`FUNCTIONUSETUWEIGHTUCALLBACKUTHRESHOLD = 4
  • BrickletLoadCell`FUNCTIONUSETUDEBOUNCEUPERIOD = 6
  • BrickletLoadCell`FUNCTIONUSETUMOVINGUAVERAGE = 8
  • BrickletLoadCell`FUNCTIONULEDUON = 10
  • BrickletLoadCell`FUNCTIONULEDUOFF = 11
  • BrickletLoadCell`FUNCTIONUCALIBRATE = 13
  • BrickletLoadCell`FUNCTIONUTARE = 14
  • BrickletLoadCell`FUNCTIONUSETUCONFIGURATION = 15
BrickletLoadCell@SetResponseExpected[functionId, responseExpected] → Null
Parameters:
  • functionId – Type: Integer, Range: See constants
  • responseExpected – Type: True/False

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 functionId:

  • BrickletLoadCell`FUNCTIONUSETUWEIGHTUCALLBACKUPERIOD = 2
  • BrickletLoadCell`FUNCTIONUSETUWEIGHTUCALLBACKUTHRESHOLD = 4
  • BrickletLoadCell`FUNCTIONUSETUDEBOUNCEUPERIOD = 6
  • BrickletLoadCell`FUNCTIONUSETUMOVINGUAVERAGE = 8
  • BrickletLoadCell`FUNCTIONULEDUON = 10
  • BrickletLoadCell`FUNCTIONULEDUOFF = 11
  • BrickletLoadCell`FUNCTIONUCALIBRATE = 13
  • BrickletLoadCell`FUNCTIONUTARE = 14
  • BrickletLoadCell`FUNCTIONUSETUCONFIGURATION = 15
BrickletLoadCell@SetResponseExpectedAll[responseExpected] → Null
Parameters:
  • responseExpected – Type: True/False

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

Constants

BrickletLoadCell`DEVICEUIDENTIFIER

This constant is used to identify a Load Cell Bricklet.

The GetIdentity[] function and the IPConnection@EnumerateCallback callback of the IP Connection have a deviceIdentifier parameter to specify the Brick's or Bricklet's type.

BrickletLoadCell`DEVICEDISPLAYNAME

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