Shell - Dual Relay Bricklet

This is the description of the Shell 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 Shell API bindings is part of their general description.

Examples

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

Simple

Download (example-simple.sh)

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#!/bin/sh
# Connects to localhost:4223 by default, use --host and --port to change this

uid=XYZ # Change XYZ to the UID of your Dual Relay Bricklet

# Turn relays alternating on/off 10 times with 1 second delay
for i in 0 1 2 3 4; do
    sleep 1
    tinkerforge call dual-relay-bricklet $uid set-state true false
    sleep 1
    tinkerforge call dual-relay-bricklet $uid set-state false true
done

API

Possible exit codes for all tinkerforge commands are:

  • 1: interrupted (ctrl+c)
  • 2: syntax error
  • 21: Python 2.5 or newer is required
  • 22: Python argparse module is missing
  • 23: socket error
  • 24: other exception
  • 25: invalid placeholder in format string
  • 26: authentication error
  • 201: timeout occurred
  • 209: invalid argument value
  • 210: function is not supported
  • 211: unknown error

Command Structure

The common options of the call and dispatch commands are documented here. The specific command structure is shown below.

tinkerforge call dual-relay-bricklet [<option>..] <uid> <function> [<argument>..]
Parameters:
  • <uid> -- string
  • <function> -- string

The call command is used to call a function of the Dual Relay Bricklet. It can take several options:

  • --help shows help for the specific call command and exits
  • --list-functions shows a list of known functions of the Dual Relay Bricklet and exits
tinkerforge dispatch dual-relay-bricklet [<option>..] <uid> <callback>
Parameters:
  • <uid> -- string
  • <callback> -- string

The dispatch command is used to dispatch a callback of the Dual Relay Bricklet. It can take several options:

  • --help shows help for the specific dispatch command and exits
  • --list-callbacks shows a list of known callbacks of the Dual Relay Bricklet and exits
tinkerforge call dual-relay-bricklet <uid> <function> [<option>..] [<argument>..]
Parameters:
  • <uid> -- string
  • <function> -- string

The <function> to be called can take different options depending of its kind. All functions can take the following options:

  • --help shows help for the specific function and exits

Getter functions can take the following options:

  • --execute <command> shell command line to execute for each incoming response (see section about output formatting for details)

Setter functions can take the following options:

  • --expect-response requests response and waits for it

The --expect-response option for setter functions allows to detect timeouts and other error conditions calls of setters as well. The device will then send a response for this purpose. If this option is not given for a setter function then no response is send and errors are silently ignored, because they cannot be detected.

tinkerforge dispatch dual-relay-bricklet <uid> <callback> [<option>..]
Parameters:
  • <uid> -- string
  • <callback> -- string

The <callback> to be dispatched can take several options:

  • --help shows help for the specific callback and exits
  • --execute <command> shell command line to execute for each incoming response (see section about output formatting for details)

Basic Functions

tinkerforge call dual-relay-bricklet <uid> set-state <relay1> <relay2>
Parameters:
  • <relay1> -- bool
  • <relay2> -- bool
Output:

no output

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 get-state or you can use set-selected-state.

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

The default value is (false, false).

tinkerforge call dual-relay-bricklet <uid> get-state
Output:
  • relay1 -- bool
  • relay2 -- bool

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

Advanced Functions

tinkerforge call dual-relay-bricklet <uid> set-monoflop <relay> <state> <time>
Parameters:
  • <relay> -- int
  • <state> -- bool
  • <time> -- int
Output:

no output

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.

tinkerforge call dual-relay-bricklet <uid> get-monoflop <relay>
Parameters:
  • <relay> -- int
Output:
  • state -- bool
  • time -- int
  • time-remaining -- int

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

tinkerforge call dual-relay-bricklet <uid> set-selected-state <relay> <state>
Parameters:
  • <relay> -- int
  • <state> -- bool
Output:

no output

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

The other relay remains untouched.

tinkerforge call dual-relay-bricklet <uid> get-identity
Output:
  • uid -- string
  • connected-uid -- string
  • position -- char
  • hardware-version -- int,int,int
  • firmware-version -- int,int,int
  • device-identifier -- int (has symbols)

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

Callbacks

Callbacks can be used to receive time critical or recurring data from the device:

tinkerforge dispatch dual-relay-bricklet <uid> example

The available callbacks 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.

tinkerforge dispatch dual-relay-bricklet <uid> monoflop-done
Output:
  • relay -- int
  • state -- bool

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).