I am running a process on a S7-1200 plc and I need it to send a start signal to my python script, after the script is done running it needs to send something back to the plc to initiate the next phase. Oh, and it has to be done in ladder.
Is there a quick and dirty way to send things over profibus or am I better off using just a RS232 thing?
There is a commercial library called "S7connector" by Rothenbacher GmbH (obviously it's not the "s7connector" on sourceforge).
It is for the .NET framework, so could be used with IronPython.
It does work with S7-1200 PLCs. You just have to make sure a DB you want to read from / write to is not an optimized S7-1200 style DB, but a S7-300/400 compatible one, an option which you can set when creating a DB in TIA portal.
This lib also allows to read and write all I/O ports - the "shadow registers" (not sure what they're called officially) and directly as well, overriding the former.
How can I communicate between a Siemens S7-1200 and python?