load_cell_bricklet

package
Version: v0.0.0-...-1640943 Latest Latest
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Published: May 7, 2021 License: CC0-1.0 Imports: 5 Imported by: 0

Documentation

Overview

Measures weight with a load cell.

See also the documentation here: https://www.tinkerforge.com/en/doc/Software/Bricklets/LoadCell_Bricklet_Go.html.

Index

Constants

View Source
const DeviceDisplayName = "Load Cell Bricklet"
View Source
const DeviceIdentifier = 253

Variables

This section is empty.

Functions

This section is empty.

Types

type Function

type Function = uint8
const (
	FunctionGetWeight                  Function = 1
	FunctionSetWeightCallbackPeriod    Function = 2
	FunctionGetWeightCallbackPeriod    Function = 3
	FunctionSetWeightCallbackThreshold Function = 4
	FunctionGetWeightCallbackThreshold Function = 5
	FunctionSetDebouncePeriod          Function = 6
	FunctionGetDebouncePeriod          Function = 7
	FunctionSetMovingAverage           Function = 8
	FunctionGetMovingAverage           Function = 9
	FunctionLEDOn                      Function = 10
	FunctionLEDOff                     Function = 11
	FunctionIsLEDOn                    Function = 12
	FunctionCalibrate                  Function = 13
	FunctionTare                       Function = 14
	FunctionSetConfiguration           Function = 15
	FunctionGetConfiguration           Function = 16
	FunctionGetIdentity                Function = 255
	FunctionCallbackWeight             Function = 17
	FunctionCallbackWeightReached      Function = 18
)

type Gain

type Gain = uint8
const (
	Gain128x Gain = 0
	Gain64x  Gain = 1
	Gain32x  Gain = 2
)

type LoadCellBricklet

type LoadCellBricklet struct {
	// contains filtered or unexported fields
}

func New

Creates an object with the unique device ID `uid`. This object can then be used after the IP Connection `ipcon` is connected.

func (*LoadCellBricklet) Calibrate

func (device *LoadCellBricklet) Calibrate(weight uint32) (err error)

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.

func (*LoadCellBricklet) DeregisterWeightCallback

func (device *LoadCellBricklet) DeregisterWeightCallback(registrationId uint64)

Remove a registered Weight callback.

func (*LoadCellBricklet) DeregisterWeightReachedCallback

func (device *LoadCellBricklet) DeregisterWeightReachedCallback(registrationId uint64)

Remove a registered Weight Reached callback.

func (*LoadCellBricklet) GetAPIVersion

func (device *LoadCellBricklet) GetAPIVersion() [3]uint8

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.

func (*LoadCellBricklet) GetConfiguration

func (device *LoadCellBricklet) GetConfiguration() (rate Rate, gain Gain, err error)

Returns the configuration as set by SetConfiguration.

Associated constants:

* Rate10Hz
* Rate80Hz
* Gain128x
* Gain64x
* Gain32x

func (*LoadCellBricklet) GetDebouncePeriod

func (device *LoadCellBricklet) GetDebouncePeriod() (debounce uint32, err error)

Returns the debounce period as set by SetDebouncePeriod.

func (*LoadCellBricklet) GetIdentity

func (device *LoadCellBricklet) GetIdentity() (uid string, connectedUid string, position rune, hardwareVersion [3]uint8, firmwareVersion [3]uint8, deviceIdentifier uint16, err error)

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 <isolator_bricklet>` is always at position 'z'.

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

func (*LoadCellBricklet) GetMovingAverage

func (device *LoadCellBricklet) GetMovingAverage() (average uint8, err error)

Returns the length moving average as set by SetMovingAverage.

func (*LoadCellBricklet) GetResponseExpected

func (device *LoadCellBricklet) GetResponseExpected(functionID Function) (bool, error)

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.

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

func (*LoadCellBricklet) GetWeight

func (device *LoadCellBricklet) GetWeight() (weight int32, err error)

Returns the currently measured weight.

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

func (*LoadCellBricklet) GetWeightCallbackPeriod

func (device *LoadCellBricklet) GetWeightCallbackPeriod() (period uint32, err error)

Returns the period as set by SetWeightCallbackPeriod.

func (*LoadCellBricklet) GetWeightCallbackThreshold

func (device *LoadCellBricklet) GetWeightCallbackThreshold() (option ThresholdOption, min int32, max int32, err error)

Returns the threshold as set by SetWeightCallbackThreshold.

Associated constants:

* ThresholdOptionOff
* ThresholdOptionOutside
* ThresholdOptionInside
* ThresholdOptionSmaller
* ThresholdOptionGreater

func (*LoadCellBricklet) IsLEDOn

func (device *LoadCellBricklet) IsLEDOn() (on bool, err error)

Returns *true* if the led is on, *false* otherwise.

func (*LoadCellBricklet) LEDOff

func (device *LoadCellBricklet) LEDOff() (err error)

Turns the LED off.

func (*LoadCellBricklet) LEDOn

func (device *LoadCellBricklet) LEDOn() (err error)

Turns the LED on.

func (*LoadCellBricklet) RegisterWeightCallback

func (device *LoadCellBricklet) RegisterWeightCallback(fn func(int32)) uint64

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

func (*LoadCellBricklet) RegisterWeightReachedCallback

func (device *LoadCellBricklet) RegisterWeightReachedCallback(fn func(int32)) uint64

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.

func (*LoadCellBricklet) SetConfiguration

func (device *LoadCellBricklet) SetConfiguration(rate Rate, gain Gain) (err error)

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.

Associated constants:

* Rate10Hz
* Rate80Hz
* Gain128x
* Gain64x
* Gain32x

func (*LoadCellBricklet) SetDebouncePeriod

func (device *LoadCellBricklet) SetDebouncePeriod(debounce uint32) (err error)

Sets the period with which the threshold callback

* RegisterWeightReachedCallback

is triggered, if the threshold

* SetWeightCallbackThreshold

keeps being reached.

func (*LoadCellBricklet) SetMovingAverage

func (device *LoadCellBricklet) SetMovingAverage(average uint8) (err error)

Sets the length of a 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.

func (*LoadCellBricklet) SetResponseExpected

func (device *LoadCellBricklet) SetResponseExpected(functionID Function, responseExpected bool) error

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.

func (*LoadCellBricklet) SetResponseExpectedAll

func (device *LoadCellBricklet) SetResponseExpectedAll(responseExpected bool)

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

func (*LoadCellBricklet) SetWeightCallbackPeriod

func (device *LoadCellBricklet) SetWeightCallbackPeriod(period uint32) (err error)

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

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

func (*LoadCellBricklet) SetWeightCallbackThreshold

func (device *LoadCellBricklet) SetWeightCallbackThreshold(option ThresholdOption, min int32, max int32) (err error)

Sets the thresholds for the RegisterWeightReachedCallback 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)

Associated constants:

* ThresholdOptionOff
* ThresholdOptionOutside
* ThresholdOptionInside
* ThresholdOptionSmaller
* ThresholdOptionGreater

func (*LoadCellBricklet) Tare

func (device *LoadCellBricklet) Tare() (err error)

Sets the currently measured weight as tare weight.

type Rate

type Rate = uint8
const (
	Rate10Hz Rate = 0
	Rate80Hz Rate = 1
)

type ThresholdOption

type ThresholdOption = rune
const (
	ThresholdOptionOff     ThresholdOption = 'x'
	ThresholdOptionOutside ThresholdOption = 'o'
	ThresholdOptionInside  ThresholdOption = 'i'
	ThresholdOptionSmaller ThresholdOption = '<'
	ThresholdOptionGreater ThresholdOption = '>'
)

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