I would like use arduino nano with SCADA Movicon. I connected arduino with Movicon, please have a look attached file with screen shots. But buton on pin 2 and var0002 doesn't work.
These buttons use to work with Modbus Function 5. Buttons use to write to a coil or boolean variable.
You should make sure that your Modbus Library implements this function 5. In other topic, I posted my own Modbus library that implements it. It has been successufully tested with a Modbus Master simulator.