Relay functions of the FDP3-BMS (and FDP3-BMS AHU modified version) can be inverted using Modbus.
Following values need to be written to following Modbus Holding Registers to invert the relay functions:
- Invert Relay 1:
Holding Register 11202
value = 0: default (not inverted)
value = 1: inverted - Invert Relay 2:
Holding Register 11204
value = 0: default (not inverted)
value = 1: inverted
Please note that the relays should only be inverted if really necessary.
Note that in the case of the (standard) FDP3-BMS interface the interface must be set to FDP3 Standard BMS mode to be able to write to it with Modbus. Once the relay configuration has been changed another operation mode of the FDP3-BMS can be set using the DIP switches.