# Getting Error\_ExpressionEval error in SCADA **URL:** \ **Category:** Ignition\ **Tags:** scripting\ **Created:** [May 28, 2026, 7:30pm UTC](https://forum.inductiveautomation.com/t/getting-error-expressioneval-error-in-scada/115758 "2026-05-28T19:30:19Z")\ **Posts on this page:** 11\ **Page:** 1
**Author:** ![krchavav](https://avatars.discourse-cdn.com/v4/letter/k/a183cd/32.png) [@krchavav](https://forum.inductiveautomation.com/u/krchavav)\ **Post date:** [May 28, 2026, 7:30pm UTC](https://forum.inductiveautomation.com/t/getting-error-expressioneval-error-in-scada/115758/1 "2026-05-28T19:30:19Z")
I ran into an issue where it is throwing Error\_ExpressionEval error in SCADA. I have a few tags that those are link to the script and their value is showing above error. is there any fix to this? I encountered these error after I restored the backup. ![image (2)](https://us1.discourse-cdn.com/inductiveautomation/original/3X/a/5/a59c5419e250bb75c62d58d0a61b520744588820.png) ---
**Author:** ![dkhayes117](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/dkhayes117/32/68344_2.png) [@dkhayes117](https://forum.inductiveautomation.com/u/dkhayes117)\ **Post date:** [May 28, 2026, 8:08pm UTC](https://forum.inductiveautomation.com/t/getting-error-expressioneval-error-in-scada/115758/2 "2026-05-28T20:08:03Z")
I might be way off here, but try opening one of the tags and look at the expression being used. You might could even post the expression here. ---
**Author:** ![krchavav](https://avatars.discourse-cdn.com/v4/letter/k/a183cd/32.png) [@krchavav](https://forum.inductiveautomation.com/u/krchavav)\ **Post date:** [May 29, 2026, 11:23am UTC](https://forum.inductiveautomation.com/t/getting-error-expressioneval-error-in-scada/115758/3 "2026-05-29T11:23:32Z")
![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/b/f/bfdb4e217ea2ac431fba95203b29694c6af4524c.jpeg) This is the Expression error and I was thinking could it be the name in the gateway project scripting issue as I restore the backup and what if the name is incorrect in gateway ? ---
**Author:** ![JVDM](https://avatars.discourse-cdn.com/v4/letter/j/ac8455/32.png) [@JVDM](https://forum.inductiveautomation.com/u/JVDM)\ **Post date:** [May 29, 2026, 11:56am UTC](https://forum.inductiveautomation.com/t/getting-error-expressioneval-error-in-scada/115758/4 "2026-05-29T11:56:25Z")
In the docs, Error\_ExpressionEval is described as "The source expression was unable to be executed." For us to help you the best, we'd have to see the actual expression. ---
**Author:** ![dkhayes117](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/dkhayes117/32/68344_2.png) [@dkhayes117](https://forum.inductiveautomation.com/u/dkhayes117)\ **Post date:** [May 29, 2026, 11:59am UTC](https://forum.inductiveautomation.com/t/getting-error-expressioneval-error-in-scada/115758/5 "2026-05-29T11:59:42Z")
> [@JVDM](#): > > For us to help you the best, we'd have to see the actual expression. And in this case, the script, as it's a `runScript` expression. ---
**Author:** ![krchavav](https://avatars.discourse-cdn.com/v4/letter/k/a183cd/32.png) [@krchavav](https://forum.inductiveautomation.com/u/krchavav)\ **Post date:** [May 29, 2026, 12:35pm UTC](https://forum.inductiveautomation.com/t/getting-error-expressioneval-error-in-scada/115758/6 "2026-05-29T12:35:18Z")
> [@dkhayes117](#): > > And in this case, the script, as it's a `runScript` expression. ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/2/2/2216e947cf8680e7fea264d1e2dd68bd8e28cf21.png) ---
**Author:** ![dkhayes117](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/dkhayes117/32/68344_2.png) [@dkhayes117](https://forum.inductiveautomation.com/u/dkhayes117)\ **Post date:** [May 29, 2026, 12:40pm UTC](https://forum.inductiveautomation.com/t/getting-error-expressioneval-error-in-scada/115758/7 "2026-05-29T12:40:01Z")
That's the expression, not the script. The error is coming from the script that the expression is calling. Also, once you fix the error, I would look to change the expression tags to memory tags and use a gateway timer or scheduled script to write to them. `RunScript` should only be used with scripts the have very fast execution times, like single digit millis. Otherwise, other tags might be delayed in their execution. ---
**Author:** ![krchavav](https://avatars.discourse-cdn.com/v4/letter/k/a183cd/32.png) [@krchavav](https://forum.inductiveautomation.com/u/krchavav)\ **Post date:** [May 29, 2026, 12:48pm UTC](https://forum.inductiveautomation.com/t/getting-error-expressioneval-error-in-scada/115758/8 "2026-05-29T12:48:19Z")
Okay..I will look into the script and check with my seniors with next step. Thank you. ---
**Author:** ![mpoulsen921](https://avatars.discourse-cdn.com/v4/letter/m/b4bc9f/32.png) [@mpoulsen921](https://forum.inductiveautomation.com/u/mpoulsen921)\ **Post date:** [May 29, 2026, 1:01pm UTC](https://forum.inductiveautomation.com/t/getting-error-expressioneval-error-in-scada/115758/9 "2026-05-29T13:01:08Z")
Have you checked and made sure that the project where the script is located is the one you have selected in the Gateway config page for the Gateway Scripting Project? Otherwise, it can't be called from tags. ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/e/c/ec7905ad32f5a4e3c88efb59dd119bfab70f1374.png) ---
**Author:** ![krchavav](https://avatars.discourse-cdn.com/v4/letter/k/a183cd/32.png) [@krchavav](https://forum.inductiveautomation.com/u/krchavav)\ **Post date:** [May 29, 2026, 1:03pm UTC](https://forum.inductiveautomation.com/t/getting-error-expressioneval-error-in-scada/115758/10 "2026-05-29T13:03:48Z")
The project file name is Copy\_of\_TGW\_Ama\_TX\_1 and in the Gateway scripting project it name as a TGW\_Ama\_TX ---
**Author:** ![mpoulsen921](https://avatars.discourse-cdn.com/v4/letter/m/b4bc9f/32.png) [@mpoulsen921](https://forum.inductiveautomation.com/u/mpoulsen921)\ **Post date:** [May 29, 2026, 1:26pm UTC](https://forum.inductiveautomation.com/t/getting-error-expressioneval-error-in-scada/115758/11 "2026-05-29T13:26:40Z")
So you just have to make sure that the project name specified in the Gateway Scripting Project actually is the project that contains the script. If not, the script can't be called from the tags. From your message answer it seems like this is the culprit, if the project with the script is called Copy\_of\_TGW\_Ama\_TX\_1 and the Gateway Scripting Project is pointing to TGW\_Ama\_TX. Then the scripts defined in the expression tags can't be called. Try changing the Gateway Scripting Project to Copy\_of\_TGW\_Ama\_TX\_1 and see if that works.