# PLC Fault

**URL:** <https://forum.inductiveautomation.com/t/plc-fault/2158>\
**Category:** Ignition\
**Created:** [August 30, 2010, 11:31am UTC](https://forum.inductiveautomation.com/t/plc-fault/2158 "2010-08-30T11:31:53Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Rawlow](https://avatars.discourse-cdn.com/v4/letter/r/47e85d/32.png) [@Rawlow](https://forum.inductiveautomation.com/u/Rawlow)\
**Post date:** [August 30, 2010, 11:31am UTC](https://forum.inductiveautomation.com/t/plc-fault/2158/1 "2010-08-30T11:31:53Z")

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I am having problems with a PLC5 20/E and a 40/E with the firmware revision of A. Every time I try and add a tag to my project it faults the processors and I have to download the program to recover from the fault. The processors return a Bus Error fault has anyone experienced this problem before? One other problem I have with a ControlLogix L55 not all of my tags show up. So when I clicked on the refresh button the processor locks up. Everything continued to run but the processor drops of the network. Currently I have other processors that are working fine. Any suggestions?

Thanks  
Rawlow

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**Author:** ![thechtman](https://avatars.discourse-cdn.com/v4/letter/t/e56c9b/32.png) [@thechtman](https://forum.inductiveautomation.com/u/thechtman)\
**Post date:** [September 3, 2010, 5:00pm UTC](https://forum.inductiveautomation.com/t/plc-fault/2158/2 "2010-09-03T17:00:23Z")

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We are current working with the customer to narrow in on the source of the problem. It is happening with a fresh install of Ignition and using Kepware instead of our OPC UA server module.