How to power FP-RLY-422 relay?

[Bo]

Hi
The temperature control VI works now, but I still have one question related to power the fieldpoint
Relay. Now I cascade power to the fieldpoint bank by connecting one external power supply of 25 VDC to the V and C terminal of FP-2000, and then I connect the V and C terminals between the modules. As you said to me � All FieldPoint I/O modules are supplied operating power from the power supply in the network module. Certain modules may require additional power for sourcing power via outputs or inputs. Of the modules you list above, the following module requires external power; FP-AO-200. The following modules do not require external power wired to the V & C terminals; FP-AI-100, FP-AI-110, FP-TC-120, and FP-RLY-422� However, as I dis
connect the connection of the V and C terminal between modules, I check the voltage between V and C terminal or Vsup and COM of FP-RLY-422 with a multimeter are 0. And in this case the solid state relay can not switch and heater can not heat. Only when the V and C terminals between the modules are connected, the voltages between V and C terminal or Vsup and COM were 25 V the same as external power supply and the heater can work well.
So do I need to connect the V and C terminals between the modules? or do I need to connect additional power supply for FP-RLY-422?
Thanks a lot.

[Aaron_G]

Hi Bo,

Sorry for the confusion that resulted from my earlier reply. Let me try and clarify it. The FP-RLY-422 is an electro-mechanical relay module. It does not require power to be wired to the V & C terminals of the terminal base that it resides in, for normal operation of the relays. Since they are electro-mechanical relays, the relays simply provide a switched path between the I.Com or Internally Common pins and the Normally Open or Normally Closed pin. However, since they are simply relays, power may be switched through them to control external devices. This can be done by wiring the signal through I.Com. However, it sounds like you have wired I.Com to either the C or V terminal and thus are switching power from the V or C terminal to the Solid State Relay
s. In this case, the FP-RLY-422 is switching the power provided by the V and C terminals, but itself does not require the power provided by the V & C terminals.

I hope this clears it up.

Regards,
Aaron