Wiring to the COM terminal in a cFP DO-401 module

[anaerobesys]

Is it necessary to wire anything to the COM terminal in a cFP DO-401 output module.  I'm using the board to trigger various 24VDC outputs.  All of the loads have their common terminal wired to the power supply commong outside of the Fieldpoint Device.  I've wired the +24VDC to the V and Vsup terminals.  Do I need to wire the COM terminal for the module to function properly?  All I need the module to do is to connect the output terminal to the Vsup terminal.

[RavensFan]

As long as you are certain that you are tying the loads to the same common of the power supply that is powering the modules (as opposed to tying to some other power supply by mistake), you can tie the loads to the common of the power supply.  If you tied them to the common terminals of the module, they would all go back to the common side of the power supply anyway because there the Com terminals of the module are a direction connection to the power supply common coming into the module.

The way to be sure is, with the power off, check the resistance between the various Com terminals.  You should find they are minimal resistance.

Also, if your loads are inductive, such as coils for a relay, don't forget to put diodes across the coils of the relays.

[Graziano]

Hi!
   Vsup terminal has not to be wired to LOAD, The load should be in parallel of Vout and Com, while external power supply has to connect to Vsup and Com, as stated in Field Point operating instructions FP-DO-401.

   Note that DO-401 is Sourcing output, if you need Sinking Output it is not the right module (check, but it seems to me that DO-403 is Sinking).

   Hope this helps.

graziano