# Error\_ExpressionEval word bit

**URL:** <https://forum.inductiveautomation.com/t/error-expressioneval-word-bit/106156>\
**Category:** Ignition\
**Tags:** vision\
**Created:** [May 12, 2025, 7:02pm UTC](https://forum.inductiveautomation.com/t/error-expressioneval-word-bit/106156 "2025-05-12T19:02:06Z")\
**Posts on this page:** 9\
**Page:** 1

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**Author:** ![aaaa](https://avatars.discourse-cdn.com/v4/letter/a/eb8c5e/32.png) [@aaaa](https://forum.inductiveautomation.com/u/aaaa)\
**Post date:** [May 12, 2025, 7:02pm UTC](https://forum.inductiveautomation.com/t/error-expressioneval-word-bit/106156/1 "2025-05-12T19:02:06Z")

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Hello,

I have a word bit that I'm trying to access, so I have getBit({[default]ABC/XYZ\_2\_},0)

but I get Error\_ExpressionEval, not sure why.

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**Author:** ![ryan.white](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/ryan.white/32/73193_2.png) [@ryan.white](https://forum.inductiveautomation.com/u/ryan.white)\
**Post date:** [May 12, 2025, 7:07pm UTC](https://forum.inductiveautomation.com/t/error-expressioneval-word-bit/106156/2 "2025-05-12T19:07:02Z")

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Is your tag value Null? While in the expression editor you can hover over the error and it normally gives you some more information. What does it say when you hover over the error?

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**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:** [May 12, 2025, 7:14pm UTC](https://forum.inductiveautomation.com/t/error-expressioneval-word-bit/106156/3 "2025-05-12T19:14:21Z")

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Is `{[default]ABC/XYZ_2_}` a numeric tag? (`getBit()` only works on numbers.)

You can check by changing it to `typeOf({[default]ABC/XYZ_2_})` and look at the Binding Preview.

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<div class="post-metadata">

**Author:** ![aaaa](https://avatars.discourse-cdn.com/v4/letter/a/eb8c5e/32.png) [@aaaa](https://forum.inductiveautomation.com/u/aaaa)\
**Post date:** [May 12, 2025, 7:27pm UTC](https://forum.inductiveautomation.com/t/error-expressioneval-word-bit/106156/4 "2025-05-12T19:27:00Z")

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Value is "bad" so I guess that's why! Thanks

Where would you hover to get more information? I hovered over the textbox in designer, client, and also checked the gateway logs. Nothing showed up.

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<div class="post-metadata">

**Author:** ![ryan.white](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/ryan.white/32/73193_2.png) [@ryan.white](https://forum.inductiveautomation.com/u/ryan.white)\
**Post date:** [May 12, 2025, 7:29pm UTC](https://forum.inductiveautomation.com/t/error-expressioneval-word-bit/106156/5 "2025-05-12T19:29:19Z")

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> [@aaaa](#):
>
> hover

 ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/0/d/0d71bfb12701574033291120852be2cc69868549.png)

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<div class="post-metadata">

**Author:** ![aaaa](https://avatars.discourse-cdn.com/v4/letter/a/eb8c5e/32.png) [@aaaa](https://forum.inductiveautomation.com/u/aaaa)\
**Post date:** [May 12, 2025, 7:59pm UTC](https://forum.inductiveautomation.com/t/error-expressioneval-word-bit/106156/6 "2025-05-12T19:59:29Z")

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My window looks a little different, where are you seeing this?

 ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/1/a/1af6e30a1c57d69e999d3d6f3aed9554eca30121.jpeg)

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<div class="post-metadata">

**Author:** ![ryan.white](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/ryan.white/32/73193_2.png) [@ryan.white](https://forum.inductiveautomation.com/u/ryan.white)\
**Post date:** [May 12, 2025, 8:04pm UTC](https://forum.inductiveautomation.com/t/error-expressioneval-word-bit/106156/7 "2025-05-12T20:04:12Z")

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Ah, you are in Vision, and they haven't brought over the expression binding preview functionality from Perspective yet.

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<div class="post-metadata">

**Author:** ![aaaa](https://avatars.discourse-cdn.com/v4/letter/a/eb8c5e/32.png) [@aaaa](https://forum.inductiveautomation.com/u/aaaa)\
**Post date:** [May 12, 2025, 8:11pm UTC](https://forum.inductiveautomation.com/t/error-expressioneval-word-bit/106156/8 "2025-05-12T20:11:06Z")

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Ah bummer, it's a nice feature.

I'll try again once the tag is not null. Thank you @ryan.white and @Transistor

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<div class="post-metadata">

**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:** [May 13, 2025, 11:34am UTC](https://forum.inductiveautomation.com/t/error-expressioneval-word-bit/106156/9 "2025-05-13T11:34:30Z")

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You can create a memory tag for testing and set it to `null` or any other value for testing.