# Address configuration for s7 1200 + Modbus TCP

**URL:** <https://forum.inductiveautomation.com/t/address-configuration-for-s7-1200-modbus-tcp/111360>\
**Category:** Ignition\
**Tags:** designer\
**Created:** [October 11, 2025, 11:35am UTC](https://forum.inductiveautomation.com/t/address-configuration-for-s7-1200-modbus-tcp/111360 "2025-10-11T11:35:32Z")\
**Posts on this page:** 1\
**Showing post:** 13

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**Author:** ![rsrigokul](https://avatars.discourse-cdn.com/v4/letter/r/f1d935/32.png) [@rsrigokul](https://forum.inductiveautomation.com/u/rsrigokul)\
**Post date:** [October 13, 2025, 8:39am UTC](https://forum.inductiveautomation.com/t/address-configuration-for-s7-1200-modbus-tcp/111360/13 "2025-10-13T08:39:36Z")

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> [@Address configuration for s7 1200 as OPC device](https://forum.inductiveautomation.com/t/address-configuration-for-s7-1200-as-opc-device/96583/24):
>
> Based on your earlier error report, the Modbus implementation in Siemens doesn't support the necessary "Masked Write" function code to change bits in holding registers, and doesn't support the coil function codes. So, no can do with Modbus

it meant both coil and HR cannot be use for writing ?

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