1734 Point IO fusing

[NetNathan]

Would you fuse every module in a Point IO system or by groups?
I have 3 Point IO racks and about 30 modules total of assorted IO (DI, DO, AI, AO). Independent fusing would be huge.

Normally I have 1 fuse for inputs and 1 for outputs. I know this makes it a little hard to locate a fault, you usually have to disconnect wires at the terminal strip to find (I use an separate common power wire to each module from the terminal strip).

How would you fuse?

Actually, how do most of you fuse any of your PLC IO modules?

 

[Mickey]

I fuse every hot going to each field device for the inputs and every output leaving the output modules.

I don't want any one input or output to take out the whole system.

 

[Steve Etter]

i fuse every hot going to each field device for the inputs and every output leaving the output modules.

I don't want any one input or output to take out the whole system.

+1

 

[NetNathan]

My outputs are individually fused (electronically) and I will probably fuse per module.
I could see maybe fusing each input module as a group.
Individually fusing the inputs would be huge (due to quantity) and I feel a tad overkill.

 

[NetNathan]

But actually my question was about 1734 Point IO.
The modules all connect together and have a common power input to the 1734-AENTR module which is the Ethernet/IP connector. It passes the control power to the other modules. So it is a little hard to fuse each module.

 

[pino2003fr]

for AI i use intrinsically safe barrier depend the application

 

[brstilson]

But actually my question was about 1734 Point IO.
The modules all connect together and have a common power input to the 1734-AENTR module which is the Ethernet/IP connector. It passes the control power to the other modules. So it is a little hard to fuse each module.

Use the field power distributor 1734-FPD. This breaks the backplane power flow but keeps the communications intact. You can then fuse the FPD separately.

 

[NetNathan]

Use the field power distributor 1734-FPD. This breaks the backplane power flow but keeps the communications intact. You can then fuse the FPD separately.

I figured I was going to have to do that.
I already have 2 FPDs to separate Digital Outputs and Analog IO.
I will add another FPD after the 1734-AENTR.
This is actually better because I can now put the 1734-AENTR on the DC power supplying the PLC and Instrumentation and not the DC power for Digital IO.

Arghhh....Which means have to go back and edit the wire numbers on my prints because of the new slot arrangement.

For my wire number identification I use:
(#<Device type>-#<Rack>-##<Slot>-##<Point>)

Device type is:
1 for Dig In
2 for Dig Out
3 for Ana In
4 for Ana Out

Example:
To figure out id and location of wire #110203
1 = Dig Input
1 = Rack 1
02 = Slot 2
03 = Third input on module.