bboytaktix

Good afternoon Mr.PLC forum members.   We recently had a fuse blow on the wiring between a 1756-OF6CI analog out card and a control valve (which we have no feedback for - only the 0-100% output). Took a little longer to troubleshoot since we have no feedback and we also don't monitor individual channel status of the card. For input cards (1756-IF8H or IF16H), it's easy enough to use the under-range/over-range or broken wire signal to troubleshoot a blown fuse or bad connection, and activate an alarm. I have been told by our local consultant-technician that there is an equivalent monitoring bit for output cards. Reading the instruction manual for the 1756-I/O cards, the fault channel bits do not seem to have this type of function for the 1756-OF6CI. The fault bits only seem to look at the requested output values, and at the connection between card and PLC itself as far as I can tell.  Am I missing something?   thanks for your help

Good afternoon fellow members,I once again ask for your help to know if any of you have struggled with similar issues. For the past year and a half, Every 1-2 months we seem to be losing communication with one of our PLC's/racks. We have in the rack a 1756-EN2T card (revision 3.006) that will flash as if it is communicating and status OK (green LED), yet we will be unable to ping it and our operator interfaces go into error. We could also not open the web browser page of the EN2T card, nor connect to the PLC/rack through RSLogix5000. As this happened over the weekend, the local electrician was called and he tried cycling power to the rack and there was no change after it came back on (not sure how long he left power off to the rack though). The problem seemed to be fixed after we told him to pull the EN2T card out of its slot and then re-insert it.We verified the CIP cinnections for this card and it is around 98 to 101 CIP connections out of a max of 248, so not too high. the card's CPU usage is 24-29%, so no indication of problems there. EN2T Card is set to auto-negociate, just like all the other cards we use at all of our plants. Has anyone ever experienced a similar problem?Thank you in advance for all your help and knowledge-sharing!

great, thanks for the information. I was observing this DeviceNet configuration and it seems like the old drive was only mapped for 4 input/4 output bytes, and the current one is an SVX-9000. I looked at the other SVX9000 drives we have configured on this DeviceNet cards and they are all 8 input/8 output bytes, and so I believe this is where the problem lies.

Here is another question for you. Do I follow similar steps as you suggested for an SVX9000? We replaced an older model drive with this newer model and it doesn't seem to be communicating properly. It is showing that specific node to have an E77 error (device size mismatch)

Hi Ken, I followed your directions and it made a difference, the new output card settings seemed to stick when I added the devicenet adaptor back to the scanlist; the card was listed in the 'I/O summary' tab under 'outputs' as it should be. At first it was not working, I toggled the output bits and none of the output lights at the card turned on, none of our contactors flipped on. We then tried switching the card with an identical one thinking it was a card issue, still no luck. Finally, the electrician suggested also switching the backplane since we had seen backplanes being a problem before. We did this, and everything worked. thanks again for your help Ken, this DeviceNet can be a real pain, but I'm real glad there was someone to troubleshoot me through!!

One question: by auto-device replacement, are you referring to the 'Automap on Add' function when you are activating a card into the scanlist?

thank you for your help! I already tried putting the Devicenet card (I assume this is what you mean by controller) into Idle but did not try also de-selecting the 1794-ADN from the scanlist. I will give these steps a try and get back to you to let you know if it works.

Let me just begin by saying I am not the biggest fan of devicenet. I am fairly new to the field of Automation engineering, I have been working full time for about a year and a half alongside of some very good senior programmers/engineers and I am not the only one to have trouble configuring the devicenet system! We use RSLogix5000 for programming. My issue is that, I have a 1794-ADN DeviceNet flex I/O adapter with 7 cards in it (4 inputs, 3 output cards) and today we wanted to add another card (an 8th card, in slot 7). The electrician powered down the devicenet adapter, added the card as slot 7, rebooted everything and I was able to see the added 1794-OW8/A output card in slot 7 when I went to the devicenet adapter's 'parameters'. Problem is, the outputs are not getting to the card. When I toggle the bits associated to this output card, the output lights on the actual card aren't even turning on. More info: In the slot 7 1794-ADN devicenet adapter properties, when I upload and go to 'Module Configurations', I see that the 8th card is there and is the 1794-Ow8/A, but when I go to I/O summary, under outputs, that card is not listed. If I go back to module configuration and click properties for that output card, and go to flex configuration settings, the 'output words' are 00, unlike the other output cards that have 'output words' as 01-IO only. I try to change the 00 to 01-IO only and then download to the devicenet adapter with no luck (the added output card retains its precious settings when I upload again) Am I missing anything? Thanks in advance for any insight on this issue