Modbus lag

Well the terminology is a bit confusing but it goes like this

  • modbus slave is your physical slave. With modbus tcp, slave is tcp server
  • modbus master is openhab. With modbus tcp, master is the tcp client

The client (=master) initates the read/write requests.

When you used modpoll, it is another client, similar to openhab. Did you have the openhab running the same time you run modpoll?

I can think of the following ways to test this

  • run instances of diagslave, one corresponding to your slave ips. That should be five slaves corresponding to the ip addressed ending with .45, .46, .47, .48 and , .49. Start openhab and see if you get any issues.
  • you can try “simulate” opening a door by calling pollmb.py (see this section in wiki for more details)
  • run openhab against real hardware. At the same time (when opening door), run modpoll to see if you can pick up the changes. This is also a good test since the slave device will be under stress (requests bombarded by openhab)

Best,
Sami