I'm using a number of Modbus RTU devices connected to my PC through a Modbus TCP gateway. I'd like to poll all the available slave addresses to check which ones are available through my program.
What would be the best way to do this ?? I guess I could just do a read on some arbitrary register but I would like to use a method and value that's common to all devices.
The official Modbus Application Protocol guide mentions a Diagnostics function code but that seems to be for serial line devices only.