# Janitza Modbus RTU (Information)

**URL:** <https://forum.inductiveautomation.com/t/janitza-modbus-rtu-information/116792>\
**Category:** Ignition\
**Tags:** ignition81\
**Created:** [August 14, 2026, 4:06pm UTC](https://forum.inductiveautomation.com/t/janitza-modbus-rtu-information/116792 "2026-08-14T16:06:06Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Matrix\_Engineering](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/matrix_engineering/32/19781_2.png) [@Matrix\_Engineering](https://forum.inductiveautomation.com/u/Matrix_Engineering)\
**Post date:** [August 14, 2026, 4:06pm UTC](https://forum.inductiveautomation.com/t/janitza-modbus-rtu-information/116792/1 "2026-08-14T16:06:06Z")

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I've done a stack of Janitza meters to Ignition with no issue on modbus TCP, now having to do one with RTU. Have battled with it for a few hours with no joy, using a Moxa MB3170 as a protocol converter.

Finally got there, for anyone following along... try swapping the A and B lines. No question, just might help someone else.

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**Author:** ![David\_Stone](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/david_stone/32/79749_2.png) [@David\_Stone](https://forum.inductiveautomation.com/u/David_Stone)\
**Post date:** [August 15, 2026, 5:02am UTC](https://forum.inductiveautomation.com/t/janitza-modbus-rtu-information/116792/2 "2026-08-15T05:02:34Z")

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Pro tip with RTU, watch your TX/RX activity LEDs, one should blink shortly after the other, if they don’t, try a broadcast node ID or swap A/B. Even a bad request to the right node will generate a response packet.