Rust - Dual Relay Bricklet

This is the description of the Rust 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 Rust API bindings is part of their general description. Additional documentation can be found on docs.rs.

Examples

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

Simple

Download (example_simple.rs)

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use std::{error::Error, io, thread, time::Duration};
use tinkerforge::{dual_relay_bricklet::*, ip_connection::IpConnection};

const HOST: &str = "localhost";
const PORT: u16 = 4223;
const UID: &str = "XYZ"; // Change XYZ to the UID of your Dual Relay Bricklet.

fn main() -> Result<(), Box<dyn Error>> {
    let ipcon = IpConnection::new(); // Create IP connection.
    let dr = DualRelayBricklet::new(UID, &ipcon); // Create device object.

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

    // Turn relays alternating on/off 10 times with 1 second delay
    for _i in 0..5 {
        thread::sleep(Duration::from_millis(1000));
        dr.set_state(true, false);
        thread::sleep(Duration::from_millis(1000));
        dr.set_state(false, true);
    }

    println!("Press enter to exit.");
    let mut _input = String::new();
    io::stdin().read_line(&mut _input)?;
    ipcon.disconnect();
    Ok(())
}

API

To allow non-blocking usage, nearly every function of the Rust bindings returns a wrapper around a mpsc::Receiver. To block until the function has finished and get your result, call one of the receiver's recv variants. Those return either the result sent by the device, or any error occured.

Functions returning a result directly will block until the device has finished processing the request.

All functions listed below are thread-safe, those which return a receiver are lock-free.

Basic Functions

pub fn DualRelayBricklet::new(uid: &str, ip_connection: &IpConnection) → DualRelayBricklet

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

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

pub fn DualRelayBricklet::set_state(&self, relay1: bool, relay2: bool) → ConvertingReceiver<()>

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 DualRelayBricklet::get_state or you can use DualRelayBricklet::set_selected_state.

Running monoflop timers will be overwritten if this function is called.

The default value is (false, false).

pub fn DualRelayBricklet::get_state(&self) → ConvertingReceiver<State>

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

Advanced Functions

pub fn DualRelayBricklet::set_monoflop(&self, relay: u8, state: bool, time: u32) → ConvertingReceiver<()>

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 (in ms) 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.

pub fn DualRelayBricklet::get_monoflop(&self, relay: u8) → ConvertingReceiver<Monoflop>

Returns (for the given relay) the current state and the time as set by DualRelayBricklet::set_monoflop 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.

pub fn DualRelayBricklet::set_selected_state(&self, relay: u8, state: bool) → ConvertingReceiver<()>

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

The other relay remains untouched.

pub fn DualRelayBricklet::get_api_version(&self) → [u8; 3]

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.

pub fn DualRelayBricklet::get_response_expected(&mut self, function_id: u8) → bool

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 DualRelayBricklet::set_response_expected. 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 DualRelayBricklet::set_response_expected for the list of function ID constants available for this function.

pub fn DualRelayBricklet::set_response_expected(&mut self, function_id: u8, response_expected: bool) → ()

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:

  • DUAL_RELAY_BRICKLET_FUNCTION_SET_STATE = 1
  • DUAL_RELAY_BRICKLET_FUNCTION_SET_MONOFLOP = 3
  • DUAL_RELAY_BRICKLET_FUNCTION_SET_SELECTED_STATE = 6
pub fn DualRelayBricklet::set_response_expected_all(&mut self, response_expected: bool) → ()

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

pub fn DualRelayBricklet::get_identity(&self) → ConvertingReceiver<Identity>

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

Callbacks

Callbacks can be registered to receive time critical or recurring data from the device. The registration is done with the corresponding get_*_callback_receiver function, which returns a receiver for callback events.

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.

pub fn DualRelayBricklet::get_monoflop_done_callback_receiver(&self) → ConvertingCallbackReceiver<MonoflopDoneEvent>

Receivers created with this function receive Monoflop Done events.

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).

Constants

DualRelayBricklet::DEVICE_IDENTIFIER

This constant is used to identify a Dual Relay Bricklet.

The DualRelayBricklet::get_identity function and the IpConnection::get_enumerate_callback_receiver callback of the IP Connection have a device_identifier parameter to specify the Brick's or Bricklet's type.

DualRelayBricklet::DEVICE_DISPLAY_NAME

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