# Communication issue with S7-300

**URL:** <https://forum.inductiveautomation.com/t/communication-issue-with-s7-300/116185>\
**Category:** Ignition\
**Tags:** siemens\
**Created:** [June 29, 2026, 10:13am UTC](https://forum.inductiveautomation.com/t/communication-issue-with-s7-300/116185 "2026-06-29T10:13:25Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Raphael](https://avatars.discourse-cdn.com/v4/letter/r/edb3f5/32.png) [@Raphael](https://forum.inductiveautomation.com/u/Raphael)\
**Post date:** [June 29, 2026, 10:13am UTC](https://forum.inductiveautomation.com/t/communication-issue-with-s7-300/116185/1 "2026-06-29T10:13:25Z")

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Hello,

I need to read from and write to a specific DB on an S7-300 PLC.

I set up the connection using the S7-300 driver. I can read the tags, but I cannot write to them.  
There are no errors in the Gateway logs, so I suspect the issue may be on the PLC side.

I'm not very familiar with Siemens PLCs. Is there a specific parameter or setting that needs to be changed to allow writing?