# PFC200 Modbus TCP Master: Unstable connection when accessing multiple RTU devices behind TCP/RTU gateway – how to handle Unit-IDs correctly?

**URL:** <https://www.wago.community/t/pfc200-modbus-tcp-master-unstable-connection-when-accessing-multiple-rtu-devices-behind-tcp-rtu-gateway-how-to-handle-unit-ids-correctly/2509>\
**Category:** CODESYS\
**Tags:** pfc200\
**Created:** [January 15, 2026, 2:55pm UTC](https://www.wago.community/t/pfc200-modbus-tcp-master-unstable-connection-when-accessing-multiple-rtu-devices-behind-tcp-rtu-gateway-how-to-handle-unit-ids-correctly/2509 "2026-01-15T14:55:09Z")\
**Posts on this page:** 1\
**Showing post:** 3

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**Author:** ![Thruser](https://avatars.discourse-cdn.com/v4/letter/t/d26b3c/32.png) [@Thruser](https://www.wago.community/u/Thruser)\
**Post date:** [January 16, 2026, 7:10am UTC](https://www.wago.community/t/pfc200-modbus-tcp-master-unstable-connection-when-accessing-multiple-rtu-devices-behind-tcp-rtu-gateway-how-to-handle-unit-ids-correctly/2509/3 "2026-01-16T07:10:12Z")

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Hi,

you can manully program a queue/joblist like [here](https://www.wago.community/t/modbustcp-wahrend-laufzeit-server-slave-hinzufugen-auslesen-schreiben/2470), or use the digital twin like [here](https://www.wago.community/t/modbus-rtu-ecockpit-pfc100-750-8100-750-652/1530/6).

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_[View the full topic](https://www.wago.community/t/pfc200-modbus-tcp-master-unstable-connection-when-accessing-multiple-rtu-devices-behind-tcp-rtu-gateway-how-to-handle-unit-ids-correctly/2509)._