Adding DC Input Card to AC Dominant PLC Chassis

[alive15]

Good afternoon all,

I have an AB SLC 5/03 which uses multiple AC i/o cards (such as 1746-IA16 and 1746-OA16). I am using a 7-slot chassis with the first being processor, and next 4 being i/o cards. I am looking to install a 1746-IB16 (DC input card).

Question: Does the 24V supply for the input card have to come from the same 120V power supply that powers the rest of the PLC or is it acceptable to grab 24V from a different 120V power supply that does not touch the PLC at all?

Thanks,

 

[JaxGTO]

No any 24vdc power will work you just need the 0vdc on one of the COM terminals at the bottom.

 

[Ken Roach]

The I/O is electrically isolated from the PLC's logic power input (very much intentionally !).

Your 24V inputs just have to be relative to the DC Common you connect to this specific input module.

 

[alive15]

@All Thanks for the input!

 

[James Mcquade]

back up the plc program first.
you have to power down the plc rack before adding the card.

a co worker fried the power supply by not doing that.

james

 

[alive15]

For sure, for sure, thanks for the reminder.

So if you plug in a module with the power on, it will fry it? Sometimes we have I/O cards that become loose from the back-plane, but our techs just push it in, even with power on. I'm unsure why it would've fried your Power supply, especially if the slot is disabled in the program?