Go - Dual Relay Bricklet

This is the description of the Go API bindings for the Dual Relay Bricklet. General information and technical specifications for the Dual Relay 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/dual_relay_bricklet"
    "github.com/Tinkerforge/go-api-bindings/ipconnection"
    "time"
)

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

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

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

    // Turn relays alternating on/off 10 times with 1 second delay
    for i := 0; i < 5; i++ {
        time.Sleep(1000 * time.Millisecond)
        dr.SetState(true, false)
        time.Sleep(1000 * time.Millisecond)
        dr.SetState(false, true)
    }

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

API

The Dual Relay Bricklet API is defined in the package github.com/Tinkerforge/go-api-bindings/dual_relay_bricklet

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

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

which correspond to the values returned from Bricks and Bricklets.

All functions listed below are thread-safe.

Basic Functions

func dual_relay_bricklet.New(uid string, ipcon *IPConnection) (device DualRelayBricklet, err error)
Parameters:
  • uid – Type: string
  • ipcon – Type: *IPConnection
Returns:
  • device – Type: DualRelayBricklet
  • err – Type: error

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

device, err := dual_relay_bricklet.New("YOUR_DEVICE_UID", &ipcon)

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

func (*DualRelayBricklet) SetState(relay1 bool, relay2 bool) (err error)
Parameters:
  • relay1 – Type: bool, Default: false
  • relay2 – Type: bool, Default: false
Returns:
  • err – Type: error

Sets the state of the relays, true means on and false means off. For example: (true, false) turns relay 1 on and relay 2 off.

If you just want to set one of the relays and don't know the current state of the other relay, you can get the state with GetState() or you can use SetSelectedState().

All running monoflop timers will be aborted if this function is called.

func (*DualRelayBricklet) GetState() (relay1 bool, relay2 bool, err error)
Returns:
  • relay1 – Type: bool, Default: false
  • relay2 – Type: bool, Default: false
  • err – Type: error

Returns the state of the relays, true means on and false means off.

Advanced Functions

func (*DualRelayBricklet) SetMonoflop(relay uint8, state bool, time uint32) (err error)
Parameters:
  • relay – Type: uint8, Range: [1 to 2]
  • state – Type: bool
  • time – Type: uint32, Unit: 1 ms, Range: [0 to 232 - 1]
Returns:
  • err – Type: error

The first parameter can be 1 or 2 (relay 1 or relay 2). The second parameter is the desired state of the relay (true means on and false means off). The third parameter indicates the time that the relay should hold the state.

If this function is called with the parameters (1, true, 1500): Relay 1 will turn on and in 1.5s it will turn off again.

A monoflop can be used as a failsafe mechanism. For example: Lets assume you have a RS485 bus and a Dual Relay Bricklet connected to one of the slave stacks. You can now call this function every second, with a time parameter of two seconds. The relay will be on all the time. If now the RS485 connection is lost, the relay will turn off in at most two seconds.

func (*DualRelayBricklet) GetMonoflop(relay uint8) (state bool, time uint32, timeRemaining uint32, err error)
Parameters:
  • relay – Type: uint8, Range: [1 to 2]
Returns:
  • state – Type: bool
  • time – Type: uint32, Unit: 1 ms, Range: [0 to 232 - 1]
  • timeRemaining – Type: uint32, Unit: 1 ms, Range: [0 to 232 - 1]
  • err – Type: error

Returns (for the given relay) the current state and the time as set by SetMonoflop() as well as the remaining time until the state flips.

If the timer is not running currently, the remaining time will be returned as 0.

func (*DualRelayBricklet) SetSelectedState(relay uint8, state bool) (err error)
Parameters:
  • relay – Type: uint8, Range: [1 to 2]
  • state – Type: bool
Returns:
  • err – Type: error

Sets the state of the selected relay (1 or 2), true means on and false means off.

A running monoflop timer for the selected relay will be aborted if this function is called.

The other relay remains untouched.

func (*DualRelayBricklet) GetIdentity() (uid string, connectedUid string, position rune, hardwareVersion [3]uint8, firmwareVersion [3]uint8, deviceIdentifier uint16, err error)
Returns:
  • uid – Type: string, Length: up to 8
  • connectedUid – Type: string, Length: up to 8
  • position – Type: rune, Range: ['a' to 'h', 'i', 'z']
  • hardwareVersion – Type: [3]uint8
    • 0: major – Type: uint8, Range: [0 to 255]
    • 1: minor – Type: uint8, Range: [0 to 255]
    • 2: revision – Type: uint8, Range: [0 to 255]
  • firmwareVersion – Type: [3]uint8
    • 0: major – Type: uint8, Range: [0 to 255]
    • 1: minor – Type: uint8, Range: [0 to 255]
    • 2: revision – Type: uint8, Range: [0 to 255]
  • deviceIdentifier – Type: uint16, Range: [0 to 216 - 1]
  • err – Type: 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). 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.

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 with the corresponding Deregister*Callback function.

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 (*DualRelayBricklet) RegisterMonoflopDoneCallback(func(relay uint8, state bool)) (registrationId uint64)
Callback Parameters:
  • relay – Type: uint8, Range: [1 to 2]
  • state – Type: bool
Returns:
  • registrationId – Type: uint64

This callback is triggered whenever a monoflop timer reaches 0. The parameter contain the relay (1 or 2) and the current state of the relay (the state after the monoflop).

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.

func (*DualRelayBricklet) GetAPIVersion() (apiVersion [3]uint8, err error)
Returns:
  • apiVersion – Type: [3]uint8
    • 0: major – Type: uint8, Range: [0 to 255]
    • 1: minor – Type: uint8, Range: [0 to 255]
    • 2: revision – Type: uint8, Range: [0 to 255]
  • err – Type: error

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.

func (*DualRelayBricklet) GetResponseExpected(functionId uint8) (responseExpected bool, err error)
Parameters:
  • functionId – Type: uint8, Range: See constants
Returns:
  • responseExpected – Type: bool
  • err – Type: 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.

The following constants are available for this function:

For functionId:

  • dual_relay_bricklet.FunctionSetState = 1
  • dual_relay_bricklet.FunctionSetMonoflop = 3
  • dual_relay_bricklet.FunctionSetSelectedState = 6
func (*DualRelayBricklet) SetResponseExpected(functionId uint8, responseExpected bool) (err error)
Parameters:
  • functionId – Type: uint8, Range: See constants
  • responseExpected – Type: bool
Returns:
  • err – Type: 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 constants are available for this function:

For functionId:

  • dual_relay_bricklet.FunctionSetState = 1
  • dual_relay_bricklet.FunctionSetMonoflop = 3
  • dual_relay_bricklet.FunctionSetSelectedState = 6
func (*DualRelayBricklet) SetResponseExpectedAll(responseExpected bool) (err error)
Parameters:
  • responseExpected – Type: bool
Returns:
  • err – Type: error

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

Constants

dual_relay_bricklet.DeviceIdentifier

This constant is used to identify a Dual Relay 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.

dual_relay_bricklet.DeviceDisplayName

This constant represents the human readable name of a Dual Relay Bricklet.