Schneider M221 POU scan

Hi everyone,
I am an old AB guy who knows how their PLCs at least execute a program. I have just programmed a couple of Modicon M221s and have a question on how they handle a POU (their version of a subroutine). Seems to me that when you call a POU they don't execute it at that moment but set a flag? and then run the POU after the MAIN program scan? Or? Results that the POU would set are not available during the calling scan, to me kind of weird.
Think this why you can't nest POUs and maybe why they don't even call them subroutines? Pretty sure they handle timers, counters, etc in a similar manner.
Thanks

Welcome to forum!

No, it should not work that way. POUs start on page 86

https://www.google.fi/url?sa=t&rct=...rCLePdFD3-3GYZRFwMIbtQ&bvm=bv.123325700,d.d2s

Revised post

I'm sorry I should have said a "free" POU that is being used as a subroutine. POUs in the Master task are not called but scheduled. I saw nothing in the referenced literature as to how they are implemented during a scan of a program.

Hello I am new in this forum.I have the servo drive LXM32M and i want to connect with the plc Modicon M221 with Modbus Rtu.