# Siemens S7-1200 Error reading S7ReadResponse. Error code = 8104

**URL:** <https://forum.inductiveautomation.com/t/siemens-s7-1200-error-reading-s7readresponse-error-code-8104/78265>\
**Category:** Ignition\
**Created:** [August 23, 2023, 4:38am UTC](https://forum.inductiveautomation.com/t/siemens-s7-1200-error-reading-s7readresponse-error-code-8104/78265 "2023-08-23T04:38:08Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Wayne\_Wessel](https://avatars.discourse-cdn.com/v4/letter/w/58956e/32.png) [@Wayne\_Wessel](https://forum.inductiveautomation.com/u/Wayne_Wessel)\
**Post date:** [August 23, 2023, 4:38am UTC](https://forum.inductiveautomation.com/t/siemens-s7-1200-error-reading-s7readresponse-error-code-8104/78265/1 "2023-08-23T04:38:09Z")

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New to Siemens, using TIA Portal v18 with S7-1200.  
Device connection in Ignition configuration shows Connected.  
Ignition logs show "Error reading S7ReadResponse. Error code = 8104".  
I have been testing two tags which I can find in PLC tags / Default tag table:  
"ns=1;s=[PLC1]IW116" which is an analog input and shows in Ignition as "Bad"  
"ns=1;s=[PLC1]M1.5" which is Clock\_1Hz and shows in Ignition as "Error\_Configuration"

I found mention to permit PUT/GET so I set this offline and did a compile / software (rebuild all) and download to device / software (all) or do I also need a hardware compile?  
Protection / Access level was already Full access.  
There was also a mention of turning off optimized access but I am not sure where this is.  
I also tried restarting the Ignition gateway service.

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**Author:** ![zxcslo](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/zxcslo/32/61610_2.png) [@zxcslo](https://forum.inductiveautomation.com/u/zxcslo)\
**Post date:** [August 23, 2023, 5:01am UTC](https://forum.inductiveautomation.com/t/siemens-s7-1200-error-reading-s7readresponse-error-code-8104/78265/2 "2023-08-23T05:01:21Z")

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Have you done this?  
[https://support.inductiveautomation.com/hc/en-us/articles/4414608266893-Error-reading-S7ReadResponse-Error-code-8104#:~:text=This%20error%20indicates%20that%20access,partner%E2%80%9D%20needs%20to%20be%20enabled.](https://support.inductiveautomation.com/hc/en-us/articles/4414608266893-Error-reading-S7ReadResponse-Error-code-8104#:~:text=This%20error%20indicates%20that%20access,partner%E2%80%9D%20needs%20to%20be%20enabled.)  
The syntax for getting bits is `X` as: M **X** 1.5  
[https://docs.inductiveautomation.com/display/DOC81/Siemens#Siemens-AddressSyntax](https://docs.inductiveautomation.com/display/DOC81/Siemens#Siemens-AddressSyntax)  
The optimized access is for Data blocks (DB's). Right-click the data block and set it OFF

EDIT 1: And YES, after changing anything in Hardware Configuration, you need to recompile and download HW config again...

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**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:** [August 23, 2023, 12:30pm UTC](https://forum.inductiveautomation.com/t/siemens-s7-1200-error-reading-s7readresponse-error-code-8104/78265/3 "2023-08-23T12:30:00Z")

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> [@Wayne\_Wessel](#):
>
> or do I also need a hardware compile?

Yes

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<div class="post-metadata">

**Author:** ![Wayne\_Wessel](https://avatars.discourse-cdn.com/v4/letter/w/58956e/32.png) [@Wayne\_Wessel](https://forum.inductiveautomation.com/u/Wayne_Wessel)\
**Post date:** [August 23, 2023, 10:18pm UTC](https://forum.inductiveautomation.com/t/siemens-s7-1200-error-reading-s7readresponse-error-code-8104/78265/4 "2023-08-23T22:18:29Z")

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Yes, the hardware compile worked for the analog and adding the X worked for the MX1.5.  
Couldn't see data changing (poll rate 1s) so I changed to MX1.7 (0.5Hz).