# Waveshare modbus rtu relay-input read input

**URL:** <https://discourse.nodered.org/t/waveshare-modbus-rtu-relay-input-read-input/90539>\
**Category:** General\
**Created:** [29 August 2024 17:34 UTC](https://discourse.nodered.org/t/waveshare-modbus-rtu-relay-input-read-input/90539 "2024-08-29T17:34:59Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![RogierQ](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/rogierq/32/3211_2.png) [@RogierQ](https://discourse.nodered.org/u/RogierQ)\
**Post date:** [29 August 2024 17:34 UTC](https://discourse.nodered.org/t/waveshare-modbus-rtu-relay-input-read-input/90539/1 "2024-08-29T17:34:59Z")

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I connected a waveshare 8 ch output and 8 channel input to the rs485 port of my rpi200

I can control a relay with the modbus write with true / false

But

I mostly got it to get inputs  
Tried the flex connector and other solutions from internet. Most times i need to reboot to make the simple relay example work again. And no input data at all…

Link to the module is

> **[Industrial Modbus RTU 8-ch Relay Module (D) With Digital Input and RS485...](https://www.waveshare.com/modbus-rtu-relay-d.htm)**
>
> Industrial Modbus RTU 8-ch Relay Module (D) With Digital Input and RS485 Interface, Multi Isolation Protection Circuits, 7~36V Power Supply | Modbus RTU Relay (D)

Thanks for all ideas and suggestions!

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**Author:** ![system](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/1X/d073cd938eafa2e558d7c2cd59003b3ef4963033.png) [@system](https://discourse.nodered.org/u/system)\
**Post date:** [27 November 2024 17:35 UTC](https://discourse.nodered.org/t/waveshare-modbus-rtu-relay-input-read-input/90539/2 "2024-11-27T17:35:45Z")

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