# Show a failed OPC Connection **URL:** \ **Category:** Ignition\ **Tags:** perspective\ **Created:** [March 6, 2024, 9:12am UTC](https://forum.inductiveautomation.com/t/show-a-failed-opc-connection/86879 "2024-03-06T09:12:27Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![O\_E](https://avatars.discourse-cdn.com/v4/letter/o/c57346/32.png) [@O\_E](https://forum.inductiveautomation.com/u/O_E)\ **Post date:** [March 6, 2024, 9:12am UTC](https://forum.inductiveautomation.com/t/show-a-failed-opc-connection/86879/1 "2024-03-06T09:12:27Z")
Hi Are there any way of zeroing values with a broken OPC connection ? Im playing around with a PLC with OPC-UA and Ignition Perspective. I see the values in the UDTs and OPC-UA but when i disconnect the PLC the "old" values stays on screen. I want it to preferely show Null or somthing similar to show that the OPC-UA connection has failed and that the values are not to be trusted. ---
**Author:** ![Transistor](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/transistor/32/3380_2.png) [@Transistor](https://forum.inductiveautomation.com/u/Transistor)\ **Post date:** [March 6, 2024, 9:34am UTC](https://forum.inductiveautomation.com/t/show-a-failed-opc-connection/86879/2 "2024-03-06T09:34:52Z")
The docs are rather vague on Perspective's overlay options - apart from the symbols. (Vision overlays are well documented.) > **[Quality Codes and Overlays | Ignition User Manual](https://www.docs.inductiveautomation.com/docs/8.1/platform/tags/quality-codes-and-overlays#perspective-component-overlays)** > > A Quality Code represents a level of confidence in a value. Quality codes are made up of a level (Good, Bad, Error, or Uncertain) and an integer. If a value's quality is not Good, the value generally should not be trusted. I've put in a request to [docs@inductiveautomation.com](mailto:docs@inductiveautomation.com) for some additional material in that page. Do you not get an error overlay when the tag quality goes bad? I would avoid displaying '0'. The general idea is that displaying the last known value but with an error overlay might be more useful than displaying a zero value without an overlay which might, for example, indicate that a line is stopped or the temperature is at 0°, etc. ---
**Author:** ![O\_E](https://avatars.discourse-cdn.com/v4/letter/o/c57346/32.png) [@O\_E](https://forum.inductiveautomation.com/u/O_E)\ **Post date:** [March 6, 2024, 9:47am UTC](https://forum.inductiveautomation.com/t/show-a-failed-opc-connection/86879/3 "2024-03-06T09:47:52Z")
The only thing i see changes when i unplug the PLC are OPC quality goes from Good to Uncertain\_LastKnownValue. ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/6/8/684a13bfab57208012820aba3cf755695461a1b6.png) Even the ErrorStatus seems unchanged. Only the OPC Quality. ---
**Author:** ![O\_E](https://avatars.discourse-cdn.com/v4/letter/o/c57346/32.png) [@O\_E](https://forum.inductiveautomation.com/u/O_E)\ **Post date:** [March 6, 2024, 9:56am UTC](https://forum.inductiveautomation.com/t/show-a-failed-opc-connection/86879/4 "2024-03-06T09:56:26Z")
I was looking only in the UDTs, i see the values/tags on the Page get a black dot now. ---
**Author:** ![Transistor](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/transistor/32/3380_2.png) [@Transistor](https://forum.inductiveautomation.com/u/Transistor)\ **Post date:** [March 6, 2024, 11:04am UTC](https://forum.inductiveautomation.com/t/show-a-failed-opc-connection/86879/5 "2024-03-06T11:04:55Z")
I thought it would be a red border and red dot. (I think that's how it shows up in Designer anyway.) You can always create an expression binding on the displayed value and use the Expression Language's isGood(), isBad() or isBadOrError() functions to alter the display. > **[Logic | Ignition User Manual](https://www.docs.inductiveautomation.com/docs/8.1/appendix/expression-functions/logic)** > > The following functions allow you to perform logic and evaluate values in expression bindings. ---
**Author:** ![O\_E](https://avatars.discourse-cdn.com/v4/letter/o/c57346/32.png) [@O\_E](https://forum.inductiveautomation.com/u/O_E)\ **Post date:** [March 6, 2024, 11:34am UTC](https://forum.inductiveautomation.com/t/show-a-failed-opc-connection/86879/6 "2024-03-06T11:34:51Z")
I see it depends. When i break a existing opc connection i get a black dot "UncertainLastValue" If it is a unconnected unit that has never been read i gets a red Dot/Border "Bad Connection" or other "Bad" error ---
**Author:** ![pturmel](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pturmel/32/3295_2.png) [@pturmel](https://forum.inductiveautomation.com/u/pturmel)\ **Post date:** [March 6, 2024, 1:13pm UTC](https://forum.inductiveautomation.com/t/show-a-failed-opc-connection/86879/7 "2024-03-06T13:13:42Z")
This behavior is deeply buried in Ignition's tag system and happens with all OPC connection types.