beckhoffAds

A C++ Beckhoff AMS/ADS protocol client

This is a basic implementation of a client of the AMS/ADS protocol over TCP/IP. Class BeckhoffAds allows connecting to a TwinCAT device and reading and writing variables.

Requires the ASL library. With a recent cmake it will be downloaded if needed.

Some basic usage:

BeckhoffAds plc;

plc.connect("192.168.0.2", 852);

You can also set source and target NetID and ports manually but it will try to guess if not. You will also need to set up twincat routes to remote client devices.

You can then read and write variables:

float speed = plc.readValue<float>("GVL.speed");
plc.writeValue<int>("GVL.count", 0);

You have to take into account what C++ type correspond to each ADS type (e.g. INT -> int16_t, DINT -> int32_t, REAL -> float, BOOL -> char, etc.).

You can also register notifications, so that a callback will be called when a variable changes:

plc.onChange<int>("GVL.count", [&](int value)
{
	printf("Notified of 'count' change to %i\n", value);
});

On older compilers without lambdas you can use a function pointer or a functor as the notification handler instead.

Array variables can be read/written by individual elements (with an index [] in the name):

plc.writeValue<int>("GVL.values[1]", 35);

or as a complete array.

plc.writeArray<int>("GVL.values", { 35, -5, 27 });

A specific function is used to read string values: plc.readString("GVL.name");.

Communication errors can be detected with:

plc.hasFatalError();