Hello Chandus,
The Vsup terminals are all connected to each other and to the V terminals. So if you are supplying a voltage using an external loop supply to the FP-AO-200, you will see that same voltage appearing on pins 17 and 19. Usually one connect this external loop supply to the V and the C of each module. The voltage from the external supply
determines the maximum load impedance that the FP-AO-200 can drive. With a 24 VDC loop supply, each output can drive up to 1 kΩ of load impedance. With a 5 VDC loop supply, each output can only drive up to 100 Ω.
Please let me know if I answered your questions. If I didn't, I would appreciate it if you can explain me better what are you trying to do, if you are sourcing current to a load, open loop detection, etc.
Thanks,
LA