Output card dropping out

[Gordo26 0]

Hello, I have 3 identical conveyor stations which use an XWT-OD161 output card. I've had several instances where multiple outputs should be on, but aren't. The PLC is telling the outputs to turn on but they don't come on. After opening and closing the fuse holder for that output card the outputs start working again right away. I'm assuming the problem is inherent to the wiring of the stations as one person would have wired all three stations. I have several other conveyor stations using the same output cards that are somewhat different in how they are set up and I have not experienced this problem in any of those stations. If anyone has any advice or knowledge they could help me with I would very much appreciate it. At this point I'm not sure where to start in troubleshooting the problem. Thanks, Gordo26

[BobB 58]

Noise in the power supply? Also try disconnecting the output block from the input block a few times to see if the contacts are dirty. I have had that problem before.

[Gordo26 0]

Would using a decoupling capacitor be an effective way to reduce noise in the power supply? I've used this in the past in small electronics projects and I wonder if would be of use in this situation? Thanks for your input, I really appreciate it!

[arpix 1]

Hello! Do you using some relays on the output of the PLC?

[drforsythe 15]

Check to see what the maximum allowable current per point or group is and check it against your loads. If you are driving inductive loads like relays or contactors, the inrush current could be high enough to send the output cards into current limit. Some manufacturers have output cards that reset automatically, and others latch the current limit. Check to see if the card you are using have this feature. If so, you can use small relays or optocouplers between the plc output and the device. You could also try using individual snubber devices across the outputs to limit the effects of inrush.

[Sleepy Wombat 27]

Have you tried swapping the IO block.. and if you do and the problem follows the IO block then there is something wrong with the IO block. That is one of the things I would certainly try.