You should be able to connect a dial indicator in parallel to the MP signal from the sensor that is used for the Dynon system, as long as that dial indicator is compatible with the 5 Volt supply that is used for the Dynon MPS and the dial indicator displays the proper value for a given output value from the MPS (linearity?). It would give you an additional indicator but I don't know what else it woudl add given that the Dynon system already displays the value for the Dynon MPS on the Dynon screen.
