Help Needed...Please?

Hi all,

Okay, I have been testing a couple of panels today, and I am stumped now. The first cabinet worked fine. The second cabinet, not so much.

I have a remote rack setup in the second cabinet. I am not even worried about comms right at this moment due to the issue I am having.

None of the inputs will work and all the outputs are lit.

I have a 1771-ASB in the first module, then 2 1771-IAD's, Spare slot, 2 1771-OAD's, two spare slots, then a 1771-P4S.

I have 110 going to both sides of the switches (this is an operator cabinet), but no input lights will light up.

I have 100 at the IFM Module as well (Input 1492-IFM20F ... Output 1492-IFM20F-F12-2).

I have good power thoughout the cabinet. If I keep the output card breaker on (Its a 10 A) all the indicators have about 70 VAC. I isolated the power from the cabinet just to rule out any bleed over. I am leaning towards a rack issue, but need some guidance first.

just_lionel said:

Hi all,

Okay, I have been testing a couple of panels today, and I am stumped now. The first cabinet worked fine. The second cabinet, not so much.

I have a remote rack setup in the second cabinet. I am not even worried about comms right at this moment due to the issue I am having.

None of the inputs will work and all the outputs are lit.

Click to expand...

Not sure about that one, and can only suggest that you double check your ASB dipswitch settings, and the rack dipswitch settings.

just_lionel said:

If I keep the output card breaker on (Its a 10 A) all the indicators have about 70 VAC. I isolated the power from the cabinet just to rule out any bleed over. I am leaning towards a rack issue, but need some guidance first.

Click to expand...

That smells like an open or ungrounded neutral somewhere...It is pretty easy to miss a jumper in a newly wired panel.

Well question. If the cabinets are not connected over Remote I/O at the present, the input lights on the card them selves should stil light up correct? The active light and Adapter Fault light are blink on the ASB module, but nothing is setup as of yet. I was checking all phyiscal wiring at the moment.

SW1 on the rack is set with only 2 and 5 on. This is for 1 Slot addressing and PLC Rack Restart.

On the ASB module SW1 is only 4 off and SW2 in only 1 on.

What series and revision is the ASB?

Also, what series and rev for the rack?

EDIT: And, is it to be controlled by a PLC5?

AND, lastly, in your first post I believe you referenced the part numbers for the wiring breakout boards. Double check the wiring of those. I have some on a SLC, and the labelling of the terminal block layers could be easily misunderstood.

Lionel
I will do simple one first. 70 VAC. Equipment rated for 120 ?? Properly terminated at equip?

Check output terminals on control transformer or source of 120 VAC control power. Confirm correct transformer ratio. If you have 120 there and still have 70 VAC at unit I would suspect lifted neutral also.

Disconnect both hot and neut and use another source of 120 VAC (extension cord and confirmed / tested wall receptacle will do). See what you get then.

Dan Bentler

Okay...got the inputs working, had a loose N on the IFM Module.

As for the Outputs, they still have me stumped. When hooked to the indicators lights, from N to L I get around 55 V. Take the output wire off and measure straight, I have 123 V. I do have that at the IFM Module also. I have looked at all the neutrals and they seem fine. Ground to N is 1.9 V pretty much across the board.

This is happening to both Output modules, I have changed slots, and the issue follows. Is there a setting that I missing on the board that forces outputs on? The only problem with that theory, is well, not all of them are that way. The first few read zero, around input six you start picking up the voltage...

Triac modules with no load?

Triac leakage can fool your meter. A real load on the output should pull them down though.

If I disconnect all the outputs on the IFM Modules, all the voltages read 120 v on every output.

As OKI says, are those TRIAC modules? They leak and if you measure without load, you WILL get such reading even if outputs are turned off.
put some load (maybe light bulb, contactor coil, anything that's few watts) in parallel with voltmeter and then go ahead with probing AC outputs.

I've done that as well, and even then I am reading anywhere between 70 VAC and 130VAC depending on which output point I am reading...

just_lionel said:

If I disconnect all the outputs on the IFM Modules, all the voltages read 120 v on every output.

Click to expand...

With the outputs disconnected from the load, that is normal (triac leakage). With them connected, and getting different voltages, it makes me think that some are partially loaded and others not at all.

Try connecting an incandescent lamp or relay to them and measure again.

I had a similar problem once was meassuring 330VAC where there normally would only be 220VAC and on other places there was 170 where it should had been 220VAC.
Problem was someone mixed up N from before transfo and N from after transfo.
Powersupply from cabinet was 3*380+N+PE

Oh yeah don't know for USA but here we allways have N=0V we connect it to PE

Okay, lets see if I can post a little better today than yesterday. Yesterday I was hot, tired, and fustrated.

This is what I have.

I have two 1492-IFM20F-F120-2 moudles connected witha pre-made cables with connectors on both ends.

With no load on the output I read 120VAC at the terminals from neutral. When I connect the output devices (in this case indicators lights) it drops to around 50 VAC. If I unplug the cable from the IFM Module, I have no power at all.

This is with the PLC rack completely powered off.

http://raise.rockwellautomation.com...2-ifm20f-f-2,-ifm20f-f24-2,-ifm20f-f120-2.pdf

This is the module I am using and its wiring diagram. I have tried isolating the neutral with no avail as well. I know it has to be a wiring issue somewhere. I have it wired as shown, my hot wire comes into L1 on the right, jumps to the one besidie it, then goes to L1 on the left side. My neutral comes on in the first L2 Terminal on the right side then I have the jumpers in place there as well.

These are connected to 1171-OAD modules as well.

just_lionel said:

With no load on the output I read 120VAC at the terminals from neutral. When I connect the output devices (in this case indicators lights) it drops to around 50 VAC. If I unplug the cable from the IFM Module, I have no power at all.

Click to expand...

What kind of lights are they?

If they're very low power consuming (LED for example), then that might explain your problem.

See especially pages 4 and 9 of the installation guide.

http://literature.rockwellautomation.com/idc/groups/literature/documents/in/1771-in024_-en-p.pdf

Make sure your loads are compatible with the leakage current, and that your wiring arms provide the correct connections to the card.

EDIT: If that does not pan out, put a normal wiring arm on one of the cards and wire it normally to see if the problem lies with the card or the wiring module (divide and conquer!)

L1 and L2 when I first see them make me think 220 VAC. I wish on 120 VAC they would use N instead of L2 but who am I ??

I see no voltage rating on the PDF you attached. I would double check to make dang double sure this is not a 220 VAC unit.

I know those are factory cables and should be trustworthy but I would give some thought to making sure they are made up correctly.

My acronym memory bank just failed - what is IMF??

I agree with Okie if working with triacs either make sure you have some load on outputs OR use old style meter ie Simpson 260 or 265 to give these some load OR get an adapter from Fluke (ghost voltage adapter I think they call it)

Dan Bentler