svroonland/TwinRx

.NET library for connecting with Beckhoff TwinCAT PLC via Reactive Extensions (Rx)

NOTE

As of version 4.2.172.0, the Beckhoff ADS library for .NET also includes support for Reactive Extensions, making this library obsolete. See here for more information: https://infosys.beckhoff.com/english.php?content=../content/1033/tc3_adsnetref/7312584843.html&id=

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TwinRx

TwinRx is a library for connecting a .NET application with a Beckhoff TwinCAT PLC program via Reactive Extensions (Rx) over ADS.

Features

• Create an IObservable for a PLC variable, bringing changes to the PLC variable into the Reactive world.
• Make use of Rx's extensive event processing and querying capabilities to transform the observable into events of interest.
• Stream (write) an existing IObservable to a PLC variable
• Transparently reregister the notifications after a connection loss

Requires

• .NET 4.5 or higher
• Beckhoff TwinCAT PLC (v2 or v3)

Installation

• Install the NuGet package "TwinRx" using the NuGet Package Manager in Visual Studio

Example code

using System;
using System.Reactive.Linq;
using TwinCAT.Ads;
using TwinRx;

var adsClient = new TcAdsClient();
adsClient.Connect(801); // 801 for TwinCAT 2, 851 for TwinCAT 3

var client = new TwinCatRxClient(adsClient);

var counter = client.ObservableFor<short>("MAIN.var1", 20);

// Print out each value as it changes
counter.Subscribe(v => Console.WriteLine("Variable is now:" + v));

// Print out 10 values at a time
var buffered = counter.Buffer(10);
buffered.Subscribe(v => Console.WriteLine("Last 10 values were:" + String.Join(" - ", v)));

// Values including timestamp
var valuesWithTimestamp = counter.Select(i => new Tuple<short, DateTime>(i, DateTime.Now));
valuesWithTimestamp.Subscribe(Console.WriteLine);

// Take a single value each second
valuesWithTimestamp
	.Sample(TimeSpan.FromSeconds(5))
	.Subscribe(Console.WriteLine);

var myString = client.ObservableFor<string>("MAIN.var2");
myString.Subscribe(Console.WriteLine);

// Write a value to the PLC periodically
var valueEverySecond = Observable
	.Interval(TimeSpan.FromSeconds(1))
	.Select(i => (short) i);
var writer = client.StreamTo("MAIN.var3", valueEverySecond);

// Only even ones
var evens = client.ObservableFor<short>("MAIN.var4").Where(i => i%2 == 0);
var evensWithTimestamp = evens
	.Timestamp()
	.Zip(evens.TimeInterval(), (valWithTimestamp, interval) => new { val = "Even value is " + valWithTimestamp, interval });
evensWithTimestamp.Subscribe(Console.WriteLine);