1771-IFE Analog Input Troubles

The plant I work in has recently begun a project of getting a long unused PLC 5/60 system back in working condition.

After downloading the program to the PLC, I noticed that some of the channels on a 1771-IFE Analog Input Module were not working. We replaced the transmitters (measuring differential air pressure) and verified that a signal was being sent to the module, but we were still unable to get a non-zero value into the program.

We then replaced the module, but to no avail. The run light is a solid green, and the new module is configured correctly as far as I can tell.

If anyone could lead me in the right direction as to what I could be missing, I would greatly appreciate it.

Thanks.

Fastest and easiest way would be for you to post your .rsp file for the PLC-5.
Then the experts can confirm that your setup is correct. Are you sure you are looking at the correct addresses for the channels? Usually an "N" file.

If you do post your code, please let us know which module is giving the trouble.

Rack slot group would be nice.

I fully agree with my distinguished colleague Ken Moore ... it would be a good idea to post your .RSP file and let us take a look at it ...

going one step further, you should be aware that the 1771-IFE modules have jumpers inside them - and that those jumpers must be manually set up to properly select voltage or current operation for each channel ... the jumpers also select whether differential or single-ended wiring is being used ...

another basic idea: is the IFE module located in the "local" chassis (with the processor) - or in a remote chassis? ... if it's in a remote chassis, then we'll need the DIP switch settings from that chassis (on the chassis backplane) - and the DIP switch settings from the 1771-ASB Adapter Module in the remote chassis ... all of this relates to properly addressing the Block Transfer instructions which are necessary to communicate with the IFE module ...

going forward: we can help you set this up - but we're going to need a LOT of detailed information in order to give you detailed answers ... there are a lot of pieces to this puzzle - and just ONE piece out of place will keep the system from working at all ...

we look forward to hearing from you soon ...

Thanks for your quick response.

The RSP file can be downloaded at http://www.mediafire.com/?sharekey=ec9bf6db2e4255e1ab1eab3e9fa335ca86ad256d5ca54c78

The problem lies in Ladder 2, Rung 75. The outputs that aren't working on this rung are tagged "MILL AMPS FROM DRIVE" (N70:95) and "PDT-137 AG MILL DIF PRESSURE" (N70:101). The others are working fine.

The Module in question is a 1771-IFE Revision A located in Rack 13 Slot 3.

Once again, thank you for your help. If there's any other information you would need, please let me know.

Sorry, I didn't see the second response before I posted last. The module is in a Remote Chassis, and the dip switches are all set to Differential Current.

I'm not sure about the Adaptor Module settings at the moment, but I can get back to you as soon as I find out.

I'm fairly new to PLC 5s as I'm just getting into the workforce. I just graduated from Ohio State in electrical engineering and have gone through several Rockwell Automation courses but in Logix 5000 only.

I appreciate your time and patience.

Greetings cdhoch ...

just a friendly tip: you probably should ZIP your .RSP file and post it here in this thread - you'll get much better response that way ... nothing personal but many members (myself included) don't like accessing things from other boards ...

I've got some free time this morning - if you'd like to talk through this, just clicking the link below should give you my phone number ... give me a call and I'll try to help you over the rough spots ... naturally I'll try to help over the forum as much as I can, but sometimes a few minutes of talking beats several days of typing ...

If my memory serves me correct, the card has to be configured in software as well as hardware; this is usually done in the early part of the program using a BTW instruction to transfer the configuration data.

I had similar trouble about a year ago. Some of my input channels would not work. The channels were configured properly in hardware and software. As it turns out, someone had fat-fingered an address in distant regions of the program. This caused some of the configuration data to be overwritten with erroneous numbers. It took a while to find that bug.

I just turned around in my office and looked at where I had saved several copies of the BTW instuction worksheet that AB provides to aid in programming. You need to get the datasheet for that module and see if that particular channel is configured properly.

Its not uncommon to run into a bad slot in a 1771 rack too.

edit: actually chassis 17 rack 13 have slots 5-7 available to test out by moving the card.

If you open the module configuration dialog (by clicking on the IFE module in slot 3 of rack 13 of the IO Configuration dialog), then you can see that for channel 3 there is some live data available (value is 2049 of the configured scale between 0 and 4095).
This indicates that block transfers are working OK.

This working channel is configured for voltage whereas the others are configured for current. I say that that is suspicious. You can try to move the non-working channels to some of the channels with no symbols (not used ?), remember to set the jumpers accordingly. And also verify that you have 4-20mA going trough the channel. It could be a problem with the return path.