# Error writing to tag

**URL:** <https://forum.inductiveautomation.com/t/error-writing-to-tag/2518>\
**Category:** Ignition\
**Created:** [January 17, 2011, 7:10am UTC](https://forum.inductiveautomation.com/t/error-writing-to-tag/2518 "2011-01-17T07:10:16Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![TacHuynh](https://avatars.discourse-cdn.com/v4/letter/t/e495f1/32.png) [@TacHuynh](https://forum.inductiveautomation.com/u/TacHuynh)\
**Post date:** [January 17, 2011, 7:10am UTC](https://forum.inductiveautomation.com/t/error-writing-to-tag/2518/1 "2011-01-17T07:10:16Z")

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I got an error when trying to write a numeric value to an AB Compact Logix PLC.  
here is the message:

Error writing to Tag DataOut  
Gateway Comm Mode is not Read/Write

I had set access mode in general property to Read/Write  
Using OPC QuickClient, I can read, write to the output- no problem

Any suggestion how to debug this?  
Thanks,  
Tac.

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**Author:** ![Kyle\_Chase](https://avatars.discourse-cdn.com/v4/letter/k/9de0a6/32.png) [@Kyle\_Chase](https://forum.inductiveautomation.com/u/Kyle_Chase)\
**Post date:** [January 17, 2011, 11:41am UTC](https://forum.inductiveautomation.com/t/error-writing-to-tag/2518/2 "2011-01-17T11:41:44Z")

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Your designer is in read only mode. Set it to read/write mode. Its on the top bar in under the designer menu bar.

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<div class="post-metadata">

**Author:** ![TacHuynh](https://avatars.discourse-cdn.com/v4/letter/t/e495f1/32.png) [@TacHuynh](https://forum.inductiveautomation.com/u/TacHuynh)\
**Post date:** [January 17, 2011, 10:24pm UTC](https://forum.inductiveautomation.com/t/error-writing-to-tag/2518/3 "2011-01-17T22:24:29Z")

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Thanks.