Use a "Parameter" passing macro, you can pass up to 3 params, you could pass 2 params as posiiton....
or use Brains that a custom macro can turn on an LED, and when that LED is on, you pass the values of the X and Y DROs to
your output registers for modbus, but note, only INT's will pass not doubles, if you want/need doubles then you will have to break them apart and pass them seperatly, then recommbine at the PLC side.
SCott