Go - Voltage/Current Bricklet

This is the description of the Go API bindings for the Voltage/Current Bricklet. General information and technical specifications for the Voltage/Current Bricklet are summarized in its hardware description.

An installation guide for the Go API bindings is part of their general description. Additional documentation can be found on godoc.org.

Examples

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

Simple

Download (example_simple.go)

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package main

import (
    "fmt"
    "github.com/Tinkerforge/go-api-bindings/ipconnection"
    "github.com/Tinkerforge/go-api-bindings/voltage_current_bricklet"
)

const ADDR string = "localhost:4223"
const UID string = "XYZ" // Change XYZ to the UID of your Voltage/Current Bricklet.

func main() {
    ipcon := ipconnection.New()
    defer ipcon.Close()
    vc, _ := voltage_current_bricklet.New(UID, &ipcon) // Create device object.

    ipcon.Connect(ADDR) // Connect to brickd.
    defer ipcon.Disconnect()
    // Don't use device before ipcon is connected.

    // Get current voltage.
    voltage, _ := vc.GetVoltage()
    fmt.Printf("Voltage: %f V\n", float64(voltage)/1000.0)

    // Get current current.
    current, _ := vc.GetCurrent()
    fmt.Printf("Current: %f A\n", float64(current)/1000.0)

    fmt.Print("Press enter to exit.")
    fmt.Scanln()
}

Callback

Download (example_callback.go)

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package main

import (
    "fmt"
    "github.com/Tinkerforge/go-api-bindings/ipconnection"
    "github.com/Tinkerforge/go-api-bindings/voltage_current_bricklet"
)

const ADDR string = "localhost:4223"
const UID string = "XYZ" // Change XYZ to the UID of your Voltage/Current Bricklet.

func main() {
    ipcon := ipconnection.New()
    defer ipcon.Close()
    vc, _ := voltage_current_bricklet.New(UID, &ipcon) // Create device object.

    ipcon.Connect(ADDR) // Connect to brickd.
    defer ipcon.Disconnect()
    // Don't use device before ipcon is connected.

    vc.RegisterCurrentCallback(func(current int32) {
        fmt.Printf("Current: %f A\n", float64(current)/1000.0)
    })

    // Set period for current receiver to 1s (1000ms).
    // Note: The current callback is only called every second
    //       if the current has changed since the last call!
    vc.SetCurrentCallbackPeriod(1000)

    fmt.Print("Press enter to exit.")
    fmt.Scanln()
}

Threshold

Download (example_threshold.go)

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package main

import (
    "fmt"
    "github.com/Tinkerforge/go-api-bindings/ipconnection"
    "github.com/Tinkerforge/go-api-bindings/voltage_current_bricklet"
)

const ADDR string = "localhost:4223"
const UID string = "XYZ" // Change XYZ to the UID of your Voltage/Current Bricklet.

func main() {
    ipcon := ipconnection.New()
    defer ipcon.Close()
    vc, _ := voltage_current_bricklet.New(UID, &ipcon) // Create device object.

    ipcon.Connect(ADDR) // Connect to brickd.
    defer ipcon.Disconnect()
    // Don't use device before ipcon is connected.

    // Get threshold receivers with a debounce time of 10 seconds (10000ms).
    vc.SetDebouncePeriod(10000)

    vc.RegisterPowerReachedCallback(func(power int32) {
        fmt.Printf("Power: %f W\n", float64(power)/1000.0)
    })

    // Configure threshold for power "greater than 10 W".
    vc.SetPowerCallbackThreshold('>', 10*1000, 0)

    fmt.Print("Press enter to exit.")
    fmt.Scanln()
}

API

The Voltage/Current Bricklet API is defined in the package github.com/Tinkerforge/go-api-bindings/voltage_current_bricklet

Nearly every function of the Go bindings can return an DeviceError, implementing the error interface. The error can have one of the following values:

  • DeviceErrorSuccess = 0
  • DeviceErrorInvalidParameter = 1
  • DeviceErrorFunctionNotSupported = 2
  • DeviceErrorUnknownError = 3

which correspond to the values returned from Bricks and Bricklets.

All functions listed below are thread-safe.

Basic Functions

func NewVoltageCurrentBricklet(uid string, ipcon *IPConnection) (device VoltageCurrentBricklet, err error)

Creates a new VoltageCurrentBricklet object with the unique device ID uid and adds it to the IPConnection ipcon:

This device object can be used after the IPConnection has been connected (see examples above).

func (*VoltageCurrentBricklet) GetCurrent() (current int32, err error)

Returns the current. The value is in mA and between -20000mA and 20000mA.

If you want to get the current periodically, it is recommended to use the RegisterCurrentCallback callback and set the period with SetCurrentCallbackPeriod().

func (*VoltageCurrentBricklet) GetVoltage() (voltage int32, err error)

Returns the voltage. The value is in mV and between 0mV and 36000mV.

If you want to get the voltage periodically, it is recommended to use the RegisterVoltageCallback callback and set the period with SetVoltageCallbackPeriod().

func (*VoltageCurrentBricklet) GetPower() (power int32, err error)

Returns the power. The value is in mW and between 0mV and 720000mW.

If you want to get the power periodically, it is recommended to use the RegisterPowerCallback callback and set the period with SetPowerCallbackPeriod().

func (*VoltageCurrentBricklet) SetConfiguration(averaging Averaging, voltageConversionTime uint8, currentConversionTime uint8) (err error)

Sets the configuration of the Voltage/Current Bricklet. It is possible to configure number of averages as well as voltage and current conversion time.

Averaging:

Value Number of Averages
0 1
1 4
2 16
3 64
4 128
5 256
6 512
>=7 1024

Voltage/Current conversion:

Value Conversion time
0 140µs
1 204µs
2 332µs
3 588µs
4 1.1ms
5 2.116ms
6 4.156ms
>=7 8.244ms

The default values are 3, 4 and 4 (64, 1.1ms, 1.1ms) for averaging, voltage conversion and current conversion.

The following constants are available for this function:

  • Averaging1 = 0
  • Averaging4 = 1
  • Averaging16 = 2
  • Averaging64 = 3
  • Averaging128 = 4
  • Averaging256 = 5
  • Averaging512 = 6
  • Averaging1024 = 7
func (*VoltageCurrentBricklet) GetConfiguration() (averaging Averaging, voltageConversionTime uint8, currentConversionTime uint8, err error)

Returns the configuration as set by SetConfiguration().

The following constants are available for this function:

  • Averaging1 = 0
  • Averaging4 = 1
  • Averaging16 = 2
  • Averaging64 = 3
  • Averaging128 = 4
  • Averaging256 = 5
  • Averaging512 = 6
  • Averaging1024 = 7

Advanced Functions

func (*VoltageCurrentBricklet) SetCalibration(gainMultiplier uint16, gainDivisor uint16) (err error)

Since the shunt resistor that is used to measure the current is not perfectly precise, it needs to be calibrated by a multiplier and divisor if a very precise reading is needed.

For example, if you are expecting a measurement of 1000mA and you are measuring 1023mA, you can calibrate the Voltage/Current Bricklet by setting the multiplier to 1000 and the divisor to 1023.

func (*VoltageCurrentBricklet) GetCalibration() (gainMultiplier uint16, gainDivisor uint16, err error)

Returns the calibration as set by SetCalibration().

func (*VoltageCurrentBricklet) GetAPIVersion() (apiVersion [3]uint8, err error)

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 (*VoltageCurrentBricklet) GetResponseExpected(functionId uint8) (responseExpected bool, err 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 send and errors are silently ignored, because they cannot be detected.

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

func (*VoltageCurrentBricklet) SetResponseExpected(functionId uint8, responseExpected bool) (err 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 send and errors are silently ignored, because they cannot be detected.

The following function ID constants are available for this function:

  • FunctionSetConfiguration = 4
  • FunctionSetCalibration = 6
  • FunctionSetCurrentCallbackPeriod = 8
  • FunctionSetVoltageCallbackPeriod = 10
  • FunctionSetPowerCallbackPeriod = 12
  • FunctionSetCurrentCallbackThreshold = 14
  • FunctionSetVoltageCallbackThreshold = 16
  • FunctionSetPowerCallbackThreshold = 18
  • FunctionSetDebouncePeriod = 20
func (*VoltageCurrentBricklet) SetResponseExpectedAll(responseExpected bool) (err error)

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

func (*VoltageCurrentBricklet) 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' 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

func (*VoltageCurrentBricklet) SetCurrentCallbackPeriod(period uint32) (err error)

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

The RegisterCurrentCallback callback is only triggered if the current has changed since the last triggering.

The default value is 0.

func (*VoltageCurrentBricklet) GetCurrentCallbackPeriod() (period uint32, err error)

Returns the period as set by SetCurrentCallbackPeriod().

func (*VoltageCurrentBricklet) SetVoltageCallbackPeriod(period uint32) (err error)

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

The RegisterVoltageCallback callback is only triggered if the voltage has changed since the last triggering.

The default value is 0.

func (*VoltageCurrentBricklet) GetVoltageCallbackPeriod() (period uint32, err error)

Returns the period as set by SetVoltageCallbackPeriod().

func (*VoltageCurrentBricklet) SetPowerCallbackPeriod(period uint32) (err error)

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

The RegisterPowerCallback callback is only triggered if the power has changed since the last triggering.

The default value is 0.

func (*VoltageCurrentBricklet) GetPowerCallbackPeriod() (period uint32, err error)

Returns the period as set by GetPowerCallbackPeriod().

func (*VoltageCurrentBricklet) SetCurrentCallbackThreshold(option ThresholdOption, min int32, max int32) (err error)

Sets the thresholds for the RegisterCurrentReachedCallback callback.

The following options are possible:

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

The default value is ('x', 0, 0).

The following constants are available for this function:

  • ThresholdOptionOff = 'x'
  • ThresholdOptionOutside = 'o'
  • ThresholdOptionInside = 'i'
  • ThresholdOptionSmaller = '<'
  • ThresholdOptionGreater = '>'
func (*VoltageCurrentBricklet) GetCurrentCallbackThreshold() (option ThresholdOption, min int32, max int32, err error)

Returns the threshold as set by SetCurrentCallbackThreshold().

The following constants are available for this function:

  • ThresholdOptionOff = 'x'
  • ThresholdOptionOutside = 'o'
  • ThresholdOptionInside = 'i'
  • ThresholdOptionSmaller = '<'
  • ThresholdOptionGreater = '>'
func (*VoltageCurrentBricklet) SetVoltageCallbackThreshold(option ThresholdOption, min int32, max int32) (err error)

Sets the thresholds for the RegisterVoltageReachedCallback callback.

The following options are possible:

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

The default value is ('x', 0, 0).

The following constants are available for this function:

  • ThresholdOptionOff = 'x'
  • ThresholdOptionOutside = 'o'
  • ThresholdOptionInside = 'i'
  • ThresholdOptionSmaller = '<'
  • ThresholdOptionGreater = '>'
func (*VoltageCurrentBricklet) GetVoltageCallbackThreshold() (option ThresholdOption, min int32, max int32, err error)

Returns the threshold as set by SetVoltageCallbackThreshold().

The following constants are available for this function:

  • ThresholdOptionOff = 'x'
  • ThresholdOptionOutside = 'o'
  • ThresholdOptionInside = 'i'
  • ThresholdOptionSmaller = '<'
  • ThresholdOptionGreater = '>'
func (*VoltageCurrentBricklet) SetPowerCallbackThreshold(option ThresholdOption, min int32, max int32) (err error)

Sets the thresholds for the RegisterPowerReachedCallback callback.

The following options are possible:

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

The default value is ('x', 0, 0).

The following constants are available for this function:

  • ThresholdOptionOff = 'x'
  • ThresholdOptionOutside = 'o'
  • ThresholdOptionInside = 'i'
  • ThresholdOptionSmaller = '<'
  • ThresholdOptionGreater = '>'
func (*VoltageCurrentBricklet) GetPowerCallbackThreshold() (option ThresholdOption, min int32, max int32, err error)

Returns the threshold as set by SetPowerCallbackThreshold().

The following constants are available for this function:

  • ThresholdOptionOff = 'x'
  • ThresholdOptionOutside = 'o'
  • ThresholdOptionInside = 'i'
  • ThresholdOptionSmaller = '<'
  • ThresholdOptionGreater = '>'
func (*VoltageCurrentBricklet) SetDebouncePeriod(debounce uint32) (err error)

Sets the period in ms with which the threshold callbacks

are triggered, if the thresholds

keep being reached.

The default value is 100.

func (*VoltageCurrentBricklet) GetDebouncePeriod() (debounce uint32, err error)

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 with the corresponding Register*Callback function, which returns a unique callback ID. This ID can be used to deregister the callback later.

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.

func (*VoltageCurrentBricklet) RegisterCurrentCallback(func(current int32)) (registrationId uint64)

A callback can be registered for this event with the RegisterCurrentCallback() function. This function returns the ID of the registered callback. An added callback can be removed with the DeregisterCurrentCallback(registrationId uint64) function.

This callback is triggered periodically with the period that is set by SetCurrentCallbackPeriod(). The callback parameter is the current of the sensor.

The RegisterCurrentCallback callback is only triggered if the current has changed since the last triggering.

func (*VoltageCurrentBricklet) RegisterVoltageCallback(func(voltage int32)) (registrationId uint64)

A callback can be registered for this event with the RegisterVoltageCallback() function. This function returns the ID of the registered callback. An added callback can be removed with the DeregisterVoltageCallback(registrationId uint64) function.

This callback is triggered periodically with the period that is set by SetVoltageCallbackPeriod(). The callback parameter is the voltage of the sensor.

The RegisterVoltageCallback callback is only triggered if the voltage has changed since the last triggering.

func (*VoltageCurrentBricklet) RegisterPowerCallback(func(power int32)) (registrationId uint64)

A callback can be registered for this event with the RegisterPowerCallback() function. This function returns the ID of the registered callback. An added callback can be removed with the DeregisterPowerCallback(registrationId uint64) function.

This callback is triggered periodically with the period that is set by SetPowerCallbackPeriod(). The callback parameter is the power of the sensor.

The RegisterPowerCallback callback is only triggered if the power has changed since the last triggering.

func (*VoltageCurrentBricklet) RegisterCurrentReachedCallback(func(current int32)) (registrationId uint64)

A callback can be registered for this event with the RegisterCurrentReachedCallback() function. This function returns the ID of the registered callback. An added callback can be removed with the DeregisterCurrentReachedCallback(registrationId uint64) function.

This callback is triggered when the threshold as set by SetCurrentCallbackThreshold() is reached. The callback parameter is the current of the sensor.

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

func (*VoltageCurrentBricklet) RegisterVoltageReachedCallback(func(voltage int32)) (registrationId uint64)

A callback can be registered for this event with the RegisterVoltageReachedCallback() function. This function returns the ID of the registered callback. An added callback can be removed with the DeregisterVoltageReachedCallback(registrationId uint64) function.

This callback is triggered when the threshold as set by SetVoltageCallbackThreshold() is reached. The callback parameter is the voltage of the sensor.

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

func (*VoltageCurrentBricklet) RegisterPowerReachedCallback(func(power int32)) (registrationId uint64)

A callback can be registered for this event with the RegisterPowerReachedCallback() function. This function returns the ID of the registered callback. An added callback can be removed with the DeregisterPowerReachedCallback(registrationId uint64) function.

This callback is triggered when the threshold as set by SetPowerCallbackThreshold() is reached. The callback parameter is the power of the sensor.

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

Constants

voltage_current_bricklet.DeviceIdentifier

This constant is used to identify a Voltage/Current Bricklet.

The GetIdentity() function and the (*IPConnection) RegisterEnumerateCallback callback of the IPConnection have a deviceIdentifier parameter to specify the Brick's or Bricklet's type.

voltage_current_bricklet.DeviceDisplayName

This constant represents the human readable name of a Voltage/Current Bricklet.