# Serial modus Communication error Temperature sensor with RS485

**URL:** <https://discourse.nodered.org/t/serial-modus-communication-error-temperature-sensor-with-rs485/88182>\
**Category:** General\
**Created:** [23 May 2024 05:31 UTC](https://discourse.nodered.org/t/serial-modus-communication-error-temperature-sensor-with-rs485/88182 "2024-05-23T05:31:39Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Ajinkya09](https://avatars.discourse-cdn.com/v4/letter/a/f05b48/32.png) [@Ajinkya09](https://discourse.nodered.org/u/Ajinkya09)\
**Post date:** [23 May 2024 05:31 UTC](https://discourse.nodered.org/t/serial-modus-communication-error-temperature-sensor-with-rs485/88182/1 "2024-05-23T05:31:39Z")

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I'm trying to read the temperature sensor (Pt1000) value from Node-RED.

Connection: The Pt1000 sensor is connected to a digital converter, which converts the readings into digital values. The converter is connected to the RS485 socket of the Revolution Pi (running Raspbian OS). I tried to read the value but encountered an error.  
refer attach picture.

 ![WhatsApp Image 2024-04-25 at 17.31.17_7da7c905](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/f/4/f4533ffae66a1b56ef68a1cd1554857db6d08d4f.jpeg)  
 ![WhatsApp Image 2024-04-25 at 17.31.37_9f629662](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/5/e/5ecc6620ec0b016acc37cd1509b816abfb1b3e80.jpeg)  
 ![WhatsApp Image 2024-04-25 at 17.31.48_a2cb3ad9](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/b/4/b4fdef187e6441fe0cb7173a1e13b9da1be3f0d9.jpeg)  
 ![WhatsApp Image 2024-04-25 at 17.32.04_82825a30](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/f/4/f4ed08d2050aa7edd7e78e344898b36f971883db.jpeg)

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**Author:** ![Auto351](https://avatars.discourse-cdn.com/v4/letter/a/5daacb/32.png) [@Auto351](https://discourse.nodered.org/u/Auto351)\
**Post date:** [24 May 2024 10:56 UTC](https://discourse.nodered.org/t/serial-modus-communication-error-temperature-sensor-with-rs485/88182/2 "2024-05-24T10:56:14Z")

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HI, im not to sure about your setup but im sure /dev/ttyAMA0 are the RX and TX pins on the GPIO of the PI, your are refering to a RS485 port on a PI, have to connected to the corect port ?

Have you used a thirdy party program like Modpol to verify the Modbus Slave works as you expect?

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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:** [22 August 2024 10:56 UTC](https://discourse.nodered.org/t/serial-modus-communication-error-temperature-sensor-with-rs485/88182/3 "2024-08-22T10:56:29Z")

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