ADS uses its own address system named AmsNetId to identify devices. The assignment of a devices to an AmsNetId happens via routing. Routing is handled differently on Windows and Linux and is explained for both operating systems in the sections below.
To identify each side of a route we will use the terms client and target. The client is your computer where pyads runs on. The target is you plc or remote computer which you want to connect to.
Creating routes on Windows
On Windows you don’t need to manually add the routes with pyads but instead you use the TwinCAT Router UI ( TcSystemManager) which comes with the TwinCAT installation. Have a look at the TwinCAT documentation on infosys.beckhoff.com for further details.
Creating routes on Linux
To create a new route on Linux you can simply use the Connection class. It connects to the target and creates a route to it on your client.
>>> import pyads >>> remote_ip = '192.168.0.100' >>> remote_ads = '220.127.116.11.1.1' >>> with pyads.Connection(remote_ads, pyads.PORT_TC3PLC1, remote_ip) as plc: >>> plc.read_by_name('.TAG_NAME', pyads.PLCTYPE_INT)
You still need to create a route from the target to the client. You
can do this manually on your target or you can use the function
add_route_to_plc() as explained below!
Get the AMS address of the local machine. This may need to be added to the routing table of the remote machine.
On Linux machines at least one route must be added before the
get_local_address() will function properly.
Optionally, a local AmsNetId can be manually set before adding a route. Set this to match the expected AMS ID in the remote machine’s routing table.
>> > import pyads >> > pyads.open_port() >> > pyads.set_local_address('18.104.22.168.1.1') >> > pyads.close_port()
Adding routes to a target
ADS requires you to create a route in the routing tables of both your
client and your target. How you add a route to your client is handled in
the section above. To create a route on your target you can either use
TwinCAT or you can make use of the convenience function
Here is an example of adding a route to a target (e.g. remote plc) to allow connections to a PC with the Hostname “MyPC”
>>> import pyads >>> SENDER_AMS = '22.214.171.124.1.1' >>> PLC_IP = '192.168.0.100' >>> PLC_USERNAME = 'plc_username' >>> PLC_PASSWORD = 'plc_password' >>> ROUTE_NAME = 'RouteToMyPC' >>> HOSTNAME = 'MyPC' # or IP >>> >>> pyads.open_port() >>> pyads.set_local_address(SENDER_AMS) >>> pyads.add_route_to_plc(SENDER_AMS, HOSTNAME, PLC_IP, PLC_USERNAME, PLC_PASSWORD, route_name=ROUTE_NAME) >>> pyads.close_port()
When adding the route in TwinCAT make sure to deactivate the unidirectional option.