# Error reading S7ReadResponse. Error code = 8104

**URL:** <https://forum.inductiveautomation.com/t/error-reading-s7readresponse-error-code-8104/39257>\
**Category:** Ignition\
**Tags:** ignition80\
**Created:** [October 1, 2020, 10:11am UTC](https://forum.inductiveautomation.com/t/error-reading-s7readresponse-error-code-8104/39257 "2020-10-01T10:11:39Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Robbie.Wozencroft](https://avatars.discourse-cdn.com/v4/letter/r/b3f665/32.png) [@Robbie.Wozencroft](https://forum.inductiveautomation.com/u/Robbie.Wozencroft)\
**Post date:** [October 1, 2020, 10:11am UTC](https://forum.inductiveautomation.com/t/error-reading-s7readresponse-error-code-8104/39257/1 "2020-10-01T10:11:39Z")

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Hello,

I am having an issue with a Siemens S71500 and tags in Ignition.

The tag diagnostics value comes back as [null,Bad, Tue Sep 29 15:04:59 BST 2020 (1601388299671)].

I cant seem to find the source of the Issue, the PLC has full access, and optimized block access is unticked. PUT/GET is enabled and the PLC shows it is connected to the gateway.

When i disable the three tags that are erroring, the Error reading S7ReadResponse. Error Code = 8104. Goes away.

 ![Bad Tag Snip](https://us1.discourse-cdn.com/inductiveautomation/original/3X/d/b/db463d0e3f78318ba44484ea9eeb294b2dc76025.png)

There is only these three tags that are pulling data from this PLC and we have even recompiled the program and it made no difference.

Maybe there is something simple I am missing.  
Any help would be appreciated, Thankyou.

OS: Windows Server 2016 am64  
Java version 11.0.6+10-LTS  
Ignition Version: 8.0.15 (b2020072213)  
[FUT-Ignition\_Ignition\_logs\_20201001-1058.zip](https://forum.inductiveautomation.com/uploads/short-url/mSEKAV9x6HQfzIxZ2GJWO5a45PR.zip) (1.6 MB)

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<div class="post-metadata">

**Author:** ![Kevin.Herron](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kevin.herron/32/7259_2.png) [@Kevin.Herron](https://forum.inductiveautomation.com/u/Kevin.Herron)\
**Post date:** [October 1, 2020, 12:28pm UTC](https://forum.inductiveautomation.com/t/error-reading-s7readresponse-error-code-8104/39257/2 "2020-10-01T12:28:24Z")

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What are the addresses of those 3 tags? Can you show us a screenshot of the DB definition? Is it possible you’re reading past the end of the defined data or something?

This error code comes from the PLC. I know you said you’ve already configured it correctly, but most commonly it happens when Full Access and GET/PUT have not been enabled.