NullModem
Pymodbus offers a special NullModem transport to help end-to-end test without network.
The NullModem is activated by setting host= (port= for serial) to NULLMODEM_HOST (import pymodbus.transport)
The NullModem works with the normal transport types, and simply substitutes the physical connection: - Serial (RS-485) typically using a dongle - TCP - TLS - UDP
The NullModem is currently integrated in
- Modbus<x>Client
- AsyncModbus<x>Client
- Modbus<x>Server
- AsyncModbus<x>Server
Of course the NullModem requires that server and client(s) run in the same python instance.