Modbus connection to Simulator?

Modbus connection to Simulator?

Hy everybody
I'm new to the Trio controller and to the Modbus protocol and I am trying to understand how to connect the simulator (I would like to test the program without any hardware connected first) to a server that I would be running on my pc.
So far I have written a minimal python script that opens a server that does nothing

  2. from pyModbusTCP.server import ModbusServer

  4. server = ModbusServer("127.0.0.1", 502, no_block=True)

  6. try:
  7.     print("Start server...")
  8.     server.start()
  9.     print("Server is online")
  10.     while True:
  11.         pass

  13. except:
  14.     print("Shutdown server ...")
  15.     server.stop()
  16.     print("Server is offline")
And then I run the following code on Motion Perfect:
  1. IF MODBUS(0, -1, 127,0,0,1,502,20)=TRUE THEN
        PRINT "Modbus Port Open"
        modbus_handle=VR(20)
    ELSE
        PRINT "Error opening Modbus Port"
    ENDIF
However Motion Perfect always fails to connect and the "Error opening Modbus Port" pops up every time.

Does anybody know what I am doing wrong?