Allen Bradley PLC5 Outputs Problem

[YWengineer]

Hi,

We use 1771-OBN/B output cards.

On one rack, HALF of all the output cards have gone off.
(LHS active but RHS gone off)

Please help !

Thanks.

 

[OkiePC]

Can you zip and attach the PLC-5 program to a thread? Can you tell (or show) us how these I/O are arranged in the rack(s) and configured (rack addressing mode)?

Also, have the outputs gone off in the card but remain "on" in the PLC-5?

More details, please:

EDIT: looks like the OBN does not have last state setting jumpers:
http://samplecode.rockwellautomation.com/idc/groups/literature/documents/in/1771-in034_-en-p.pdf

 

[YWengineer]

Hi,

Thanks for replying !

The program shows outputs as active but the RHS of each output card is completely off.

There has been power problems onsite, but all PSU's are now OK.

It seems to be an addressing or software issue.

The 4 output cards each have 2 banks of 18 outputs and are located in slots 9/10/11/12.

 

[OkiePC]

Are these cards in the local chassis with the PLC-5?

 

[YWengineer]

Yes.

We have tried re-downloading the program, but same error occurs.

 

[OkiePC]

Can you zip and attach a copy of the program to a reply? (The forum only allows certain file types, and .zip is one of them.)

You say you had a power problem, it's possible that the backplane comms chip was damaged. Now your power supply is okay...rack power supply or external for I/O?

Have you verified that your new power supply is performing correctly?

 

[YWengineer]

We cannot attach the program.

PSU is a 1771-P7 and is OK.

Slot addressing is 1/2.

Analogues are OK, but Dig OP's still halved. (LHS on / RHS off)

All other cards OK, so assume backplane is OK.

 

[OkiePC]

What do you mean by LHS, RHS? Left hand side, right hand side?

 

[YWengineer]

The DC Output Cards (1771-OBN/B) are 36 way.

00>17 and 00>17 again. (on each card)

The first 00>17 (LHS) are working and the second 00>17 (RHS) are off.

LHS - Left Hand Side
RHS - Right Hand Side

Thanks again for trying to help us. Having a nightmare.

 

[Mickey]

FYI
Your card is a 32 point card. Note outputs 8 & 9 are not there.
PLC5s use an octal numbering system for it's input and output cards.

What do the status indicators on the card tell you? Also the fuse indicator on the card.

 

[OkiePC]

Well, the only thing I have noticed after reading through some literature is that they are not compatible with series A chassis.

Is the I/O in RLSogix5 showing to be okay (not faulted)?

Do you have a spare chassis you can try?

So, with 1/2 slot addressing, this is outputs O:22/0 through O:31/17, correct?

When you monitor the output image in RSLogix5, are you seeing values appear in each cards' 2nd group?

 

[YWengineer]

Thanks.

Fuse Indicators not lit. Same on other PLC's that are OK.

On all output cards first 00>17 are working, but second 00>17 off.

??????????????

 

[YWengineer]

Okie..

We have no spare chassis.

You are correct in the addressing. It seems to be that the software is only aware of half of the outputs ???!!

 

[Mickey]

Thanks.

Fuse Indicators not lit. Same on other PLC's that are OK.

On all output cards first 00>17 are working, but second 00>17 off.
s
??????????????

Have they ever worked? Or did this just happen after the power problems?

Can you unseat and reseat the modules?

 

[daba]

Are you certain you are addressing the outputs correctly.

You said that the output cards are in slots 9, 10, 11, and 12.
How have you determined the numbers of these slots, by counting from the first I/O slot as 0 or 1 ?

Here is a map of the rack showing the slot numbers...