# USB RS485 - RPI4B Connection issue

**URL:** <https://discourse.nodered.org/t/usb-rs485-rpi4b-connection-issue/80066>\
**Category:** General\
**Created:** [25 July 2023 23:40 UTC](https://discourse.nodered.org/t/usb-rs485-rpi4b-connection-issue/80066 "2023-07-25T23:40:58Z")\
**Posts on this page:** 5\
**Page:** 1

<div class="post-metadata">

**Author:** ![DrdP](https://avatars.discourse-cdn.com/v4/letter/d/b5ac83/32.png) [@DrdP](https://discourse.nodered.org/u/DrdP)\
**Post date:** [25 July 2023 23:40 UTC](https://discourse.nodered.org/t/usb-rs485-rpi4b-connection-issue/80066/1 "2023-07-25T23:40:58Z")

</div>

Good day,

I am trying to read info from a RS485 soil sensor. I have gotten the ttyUSB0 to connect in Node-Red but it wont start and read the value it seems. I do not know what I need to change to get this going.

Any help would be greatly appreciated

Jul 26 11:17:13 raspberrypi Node-RED[596]: Welcome to Node-RED  
Jul 26 11:17:13 raspberrypi Node-RED[596]: ===================  
Jul 26 11:17:13 raspberrypi Node-RED[596]: 26 Jul 11:17:13 - [info] Node-RED version: v2.2.2  
Jul 26 11:17:13 raspberrypi Node-RED[596]: 26 Jul 11:17:13 - [info] Node.js version: v14.21.3  
Jul 26 11:17:13 raspberrypi Node-RED[596]: 26 Jul 11:17:13 - [info] Linux 5.10.103-v7l+ arm LE  
Jul 26 11:17:15 raspberrypi Node-RED[596]: 26 Jul 11:17:15 - [info] Loading palette nodes  
Jul 26 11:17:19 raspberrypi Node-RED[596]: 26 Jul 11:17:19 - [info] Dashboard version 3.1.6 started at /ui  
Jul 26 11:17:20 raspberrypi Node-RED[596]: 26 Jul 11:17:20 - [info] Settings file : /home/ubuntu/.node-red/settings.js  
Jul 26 11:17:20 raspberrypi Node-RED[596]: 26 Jul 11:17:20 - [info] Context store : 'default' [module=memory]  
Jul 26 11:17:20 raspberrypi Node-RED[596]: 26 Jul 11:17:20 - [info] User directory : /home/ubuntu/.node-red  
Jul 26 11:17:20 raspberrypi Node-RED[596]: 26 Jul 11:17:20 - [info] Projects directory: /home/ubuntu/.node-red/projects  
Jul 26 11:17:20 raspberrypi Node-RED[596]: 26 Jul 11:17:20 - [warn] No active project : using default flows file  
Jul 26 11:17:20 raspberrypi Node-RED[596]: 26 Jul 11:17:20 - [info] Flows file : /home/ubuntu/.node-red/flows.json  
Jul 26 11:17:20 raspberrypi Node-RED[596]: 26 Jul 11:17:20 - [info] Server now running at [http://127.0.0.1:1880/](http://127.0.0.1:1880/)  
Jul 26 11:17:20 raspberrypi Node-RED[596]: 26 Jul 11:17:20 - [warn]  
Jul 26 11:17:20 raspberrypi Node-RED[596]: ---------------------------------------------------------------------  
Jul 26 11:17:20 raspberrypi Node-RED[596]: Your flow credentials file is encrypted using a system-generated key.  
Jul 26 11:17:20 raspberrypi Node-RED[596]: If the system-generated key is lost for any reason, your credentials  
Jul 26 11:17:20 raspberrypi Node-RED[596]: file will not be recoverable, you will have to delete it and re-enter  
Jul 26 11:17:20 raspberrypi Node-RED[596]: your credentials.  
Jul 26 11:17:20 raspberrypi Node-RED[596]: You should set your own key using the 'credentialSecret' option in  
Jul 26 11:17:20 raspberrypi Node-RED[596]: your settings file. Node-RED will then re-encrypt your credentials  
Jul 26 11:17:20 raspberrypi Node-RED[596]: file using your chosen key the next time you deploy a change.  
Jul 26 11:17:20 raspberrypi Node-RED[596]: ---------------------------------------------------------------------  
Jul 26 11:17:20 raspberrypi Node-RED[596]: 26 Jul 11:17:20 - [info] Starting flows  
Jul 26 11:17:20 raspberrypi Node-RED[596]: 26 Jul 11:17:20 - [warn] [bp-modbus-client:9d1a5f85a60e2b64] Modbus new  
Jul 26 11:17:20 raspberrypi Node-RED[596]: 26 Jul 11:17:20 - [warn] [bp-modbus-client:9d1a5f85a60e2b64] Modbus initialized  
Jul 26 11:17:20 raspberrypi Node-RED[596]: 26 Jul 11:17:20 - [info] Started flows  
Jul 26 11:17:20 raspberrypi Node-RED[596]: 26 Jul 11:17:20 - [info] [serialconfig:72eb41ee046f2d0a] serial port /dev/ttyUSB0 opened at 4800 baud 8N1  
Jul 26 11:26:59 raspberrypi Node-RED[596]: 26 Jul 11:26:59 - [info] Stopping flows  
Jul 26 11:26:59 raspberrypi Node-RED[596]: 26 Jul 11:26:59 - [warn] [bp-modbus-client:9d1a5f85a60e2b64] Modbus stop fsm on close 9d1a5f85a60e2b64  
Jul 26 11:26:59 raspberrypi Node-RED[596]: 26 Jul 11:26:59 - [warn] [bp-modbus-client:9d1a5f85a60e2b64] Modbus stopped  
Jul 26 11:26:59 raspberrypi Node-RED[596]: 26 Jul 11:26:59 - [warn] [bp-modbus-client:9d1a5f85a60e2b64] Modbus stopped state without reconnecting  
Jul 26 11:26:59 raspberrypi Node-RED[596]: 26 Jul 11:26:59 - [warn] [bp-modbus-client:9d1a5f85a60e2b64] Modbus close node 9d1a5f85a60e2b64  
Jul 26 11:26:59 raspberrypi Node-RED[596]: 26 Jul 11:26:59 - [warn] [bp-modbus-client:9d1a5f85a60e2b64] Modbus Connection closed simple 9d1a5f85a60e2b64  
Jul 26 11:26:59 raspberrypi Node-RED[596]: 26 Jul 11:26:59 - [info] serial port /dev/ttyUSB0 closed  
Jul 26 11:26:59 raspberrypi Node-RED[596]: 26 Jul 11:26:59 - [info] Stopped flows  
Jul 26 11:26:59 raspberrypi Node-RED[596]: 26 Jul 11:26:59 - [info] Starting flows  
Jul 26 11:26:59 raspberrypi Node-RED[596]: 26 Jul 11:26:59 - [warn] [bp-modbus-client:9d1a5f85a60e2b64] Modbus new  
Jul 26 11:26:59 raspberrypi Node-RED[596]: 26 Jul 11:26:59 - [warn] [bp-modbus-client:9d1a5f85a60e2b64] Modbus initialized  
Jul 26 11:26:59 raspberrypi Node-RED[596]: 26 Jul 11:26:59 - [info] Started flows  
Jul 26 11:26:59 raspberrypi Node-RED[596]: 26 Jul 11:26:59 - [info] [serialconfig:72eb41ee046f2d0a] serial port /dev/ttyUSB0 opened at 4800 baud 8N1  
Jul 26 11:27:12 raspberrypi Node-RED[596]: 26 Jul 11:27:12 - [info] Stopping flows  
Jul 26 11:27:12 raspberrypi Node-RED[596]: 26 Jul 11:27:12 - [warn] [bp-modbus-client:9d1a5f85a60e2b64] Modbus stop fsm on close 9d1a5f85a60e2b64  
Jul 26 11:27:12 raspberrypi Node-RED[596]: 26 Jul 11:27:12 - [warn] [bp-modbus-client:9d1a5f85a60e2b64] Modbus stopped  
Jul 26 11:27:12 raspberrypi Node-RED[596]: 26 Jul 11:27:12 - [warn] [bp-modbus-client:9d1a5f85a60e2b64] Modbus stopped state without reconnecting  
Jul 26 11:27:12 raspberrypi Node-RED[596]: 26 Jul 11:27:12 - [warn] [bp-modbus-client:9d1a5f85a60e2b64] Modbus close node 9d1a5f85a60e2b64  
Jul 26 11:27:12 raspberrypi Node-RED[596]: 26 Jul 11:27:12 - [warn] [bp-modbus-client:9d1a5f85a60e2b64] Modbus Connection closed simple 9d1a5f85a60e2b64  
Jul 26 11:27:12 raspberrypi Node-RED[596]: 26 Jul 11:27:12 - [info] serial port /dev/ttyUSB0 closed  
Jul 26 11:27:12 raspberrypi Node-RED[596]: 26 Jul 11:27:12 - [info] Stopped flows  
Jul 26 11:27:12 raspberrypi Node-RED[596]: 26 Jul 11:27:12 - [info] Starting flows  
Jul 26 11:27:12 raspberrypi Node-RED[596]: 26 Jul 11:27:12 - [warn] [bp-modbus-client:9d1a5f85a60e2b64] Modbus new  
Jul 26 11:27:12 raspberrypi Node-RED[596]: 26 Jul 11:27:12 - [warn] [bp-modbus-client:9d1a5f85a60e2b64] Modbus initialized  
Jul 26 11:27:12 raspberrypi Node-RED[596]: 26 Jul 11:27:12 - [info] Started flows  
Jul 26 11:27:12 raspberrypi Node-RED[596]: 26 Jul 11:27:12 - [info] [serialconfig:72eb41ee046f2d0a] serial port /dev/ttyUSB0 opened at 4800 baud 8N1  
Jul 26 11:27:15 raspberrypi Node-RED[596]: 26 Jul 11:27:15 - [info] [debug:0e65b0091f7fe7dd]  
Jul 26 11:27:15 raspberrypi Node-RED[596]:   
Jul 26 11:27:25 raspberrypi Node-RED[596]: 26 Jul 11:27:25 - [info] Stopping flows  
Jul 26 11:27:25 raspberrypi Node-RED[596]: 26 Jul 11:27:25 - [warn] [bp-modbus-client:9d1a5f85a60e2b64] Modbus stop fsm on close 9d1a5f85a60e2b64  
Jul 26 11:27:25 raspberrypi Node-RED[596]: 26 Jul 11:27:25 - [warn] [bp-modbus-client:9d1a5f85a60e2b64] Modbus stopped  
Jul 26 11:27:25 raspberrypi Node-RED[596]: 26 Jul 11:27:25 - [warn] [bp-modbus-client:9d1a5f85a60e2b64] Modbus stopped state without reconnecting  
Jul 26 11:27:25 raspberrypi Node-RED[596]: 26 Jul 11:27:25 - [warn] [bp-modbus-client:9d1a5f85a60e2b64] Modbus close node 9d1a5f85a60e2b64  
Jul 26 11:27:25 raspberrypi Node-RED[596]: 26 Jul 11:27:25 - [warn] [bp-modbus-client:9d1a5f85a60e2b64] Modbus Connection closed simple 9d1a5f85a60e2b64  
Jul 26 11:27:25 raspberrypi Node-RED[596]: 26 Jul 11:27:25 - [info] serial port /dev/ttyUSB0 closed  
Jul 26 11:27:25 raspberrypi Node-RED[596]: 26 Jul 11:27:25 - [info] Stopped flows  
Jul 26 11:27:25 raspberrypi Node-RED[596]: 26 Jul 11:27:25 - [info] Starting flows  
Jul 26 11:27:25 raspberrypi Node-RED[596]: 26 Jul 11:27:25 - [warn] [bp-modbus-client:9d1a5f85a60e2b64] Modbus new  
Jul 26 11:27:25 raspberrypi Node-RED[596]: 26 Jul 11:27:25 - [warn] [bp-modbus-client:9d1a5f85a60e2b64] Modbus initialized  
Jul 26 11:27:26 raspberrypi Node-RED[596]: 26 Jul 11:27:26 - [info] Started flows  
Jul 26 11:27:26 raspberrypi Node-RED[596]: 26 Jul 11:27:26 - [info] [serialconfig:72eb41ee046f2d0a] serial port /dev/ttyUSB0 opened at 4800 baud 8N1  
Jul 26 11:27:35 raspberrypi Node-RED[596]: 26 Jul 11:27:35 - [info] Stopping flows  
Jul 26 11:27:35 raspberrypi Node-RED[596]: 26 Jul 11:27:35 - [warn] [bp-modbus-client:9d1a5f85a60e2b64] Modbus stop fsm on close 9d1a5f85a60e2b64  
Jul 26 11:27:35 raspberrypi Node-RED[596]: 26 Jul 11:27:35 - [warn] [bp-modbus-client:9d1a5f85a60e2b64] Modbus stopped  
Jul 26 11:27:35 raspberrypi Node-RED[596]: 26 Jul 11:27:35 - [warn] [bp-modbus-client:9d1a5f85a60e2b64] Modbus stopped state without reconnecting  
Jul 26 11:27:35 raspberrypi Node-RED[596]: 26 Jul 11:27:35 - [warn] [bp-modbus-client:9d1a5f85a60e2b64] Modbus close node 9d1a5f85a60e2b64  
Jul 26 11:27:35 raspberrypi Node-RED[596]: 26 Jul 11:27:35 - [warn] [bp-modbus-client:9d1a5f85a60e2b64] Modbus Connection closed simple 9d1a5f85a60e2b64  
Jul 26 11:27:35 raspberrypi Node-RED[596]: 26 Jul 11:27:35 - [info] serial port /dev/ttyUSB0 closed  
Jul 26 11:27:35 raspberrypi Node-RED[596]: 26 Jul 11:27:35 - [info] Stopped flows  
Jul 26 11:27:35 raspberrypi Node-RED[596]: 26 Jul 11:27:35 - [info] Starting flows  
Jul 26 11:27:35 raspberrypi Node-RED[596]: 26 Jul 11:27:35 - [warn] [bp-modbus-client:9d1a5f85a60e2b64] Modbus new  
Jul 26 11:27:35 raspberrypi Node-RED[596]: 26 Jul 11:27:35 - [warn] [bp-modbus-client:9d1a5f85a60e2b64] Modbus initialized  
Jul 26 11:27:35 raspberrypi Node-RED[596]: 26 Jul 11:27:35 - [info] Started flows  
Jul 26 11:27:35 raspberrypi Node-RED[596]: 26 Jul 11:27:35 - [info] [serialconfig:72eb41ee046f2d0a] serial port /dev/ttyUSB0 opened at 4800 baud 8N1  
Jul 26 11:27:52 raspberrypi Node-RED[596]: 26 Jul 11:27:52 - [info] Stopping flows  
Jul 26 11:27:52 raspberrypi Node-RED[596]: 26 Jul 11:27:52 - [warn] [bp-modbus-client:9d1a5f85a60e2b64] Modbus stop fsm on close 9d1a5f85a60e2b64  
Jul 26 11:27:52 raspberrypi Node-RED[596]: 26 Jul 11:27:52 - [warn] [bp-modbus-client:9d1a5f85a60e2b64] Modbus stopped  
Jul 26 11:27:52 raspberrypi Node-RED[596]: 26 Jul 11:27:52 - [warn] [bp-modbus-client:9d1a5f85a60e2b64] Modbus stopped state without reconnecting  
Jul 26 11:27:52 raspberrypi Node-RED[596]: 26 Jul 11:27:52 - [warn] [bp-modbus-client:9d1a5f85a60e2b64] Modbus close node 9d1a5f85a60e2b64  
Jul 26 11:27:52 raspberrypi Node-RED[596]: 26 Jul 11:27:52 - [warn] [bp-modbus-client:9d1a5f85a60e2b64] Modbus Connection closed simple 9d1a5f85a60e2b64  
Jul 26 11:27:52 raspberrypi Node-RED[596]: 26 Jul 11:27:52 - [info] serial port /dev/ttyUSB0 closed  
Jul 26 11:27:52 raspberrypi Node-RED[596]: 26 Jul 11:27:52 - [info] Stopped flows  
Jul 26 11:27:52 raspberrypi Node-RED[596]: 26 Jul 11:27:52 - [info] Starting flows  
Jul 26 11:27:52 raspberrypi Node-RED[596]: 26 Jul 11:27:52 - [warn] [bp-modbus-client:9d1a5f85a60e2b64] Modbus new  
Jul 26 11:27:52 raspberrypi Node-RED[596]: 26 Jul 11:27:52 - [warn] [bp-modbus-client:9d1a5f85a60e2b64] Modbus initialized  
Jul 26 11:27:52 raspberrypi Node-RED[596]: 26 Jul 11:27:52 - [info] Started flows  
Jul 26 11:27:52 raspberrypi Node-RED[596]: 26 Jul 11:27:52 - [info] [serialconfig:72eb41ee046f2d0a] serial port /dev/ttyUSB0 opened at 4800 baud 8N1  
Jul 26 11:33:02 raspberrypi Node-RED[596]: 26 Jul 11:33:02 - [info] Stopping flows  
Jul 26 11:33:02 raspberrypi Node-RED[596]: 26 Jul 11:33:02 - [warn] [bp-modbus-client:9d1a5f85a60e2b64] Modbus stop fsm on close 9d1a5f85a60e2b64  
Jul 26 11:33:02 raspberrypi Node-RED[596]: 26 Jul 11:33:02 - [warn] [bp-modbus-client:9d1a5f85a60e2b64] Modbus stopped  
Jul 26 11:33:02 raspberrypi Node-RED[596]: 26 Jul 11:33:02 - [warn] [bp-modbus-client:9d1a5f85a60e2b64] Modbus stopped state without reconnecting  
Jul 26 11:33:02 raspberrypi Node-RED[596]: 26 Jul 11:33:02 - [warn] [bp-modbus-client:9d1a5f85a60e2b64] Modbus close node 9d1a5f85a60e2b64  
Jul 26 11:33:02 raspberrypi Node-RED[596]: 26 Jul 11:33:02 - [warn] [bp-modbus-client:9d1a5f85a60e2b64] Modbus Connection closed simple 9d1a5f85a60e2b64  
Jul 26 11:33:02 raspberrypi Node-RED[596]: 26 Jul 11:33:02 - [info] serial port /dev/ttyUSB0 closed  
Jul 26 11:33:02 raspberrypi Node-RED[596]: 26 Jul 11:33:02 - [info] Stopped flows  
Jul 26 11:33:02 raspberrypi Node-RED[596]: 26 Jul 11:33:02 - [info] Starting flows  
Jul 26 11:33:02 raspberrypi Node-RED[596]: 26 Jul 11:33:02 - [warn] [bp-modbus-client:9d1a5f85a60e2b64] Modbus new  
Jul 26 11:33:02 raspberrypi Node-RED[596]: 26 Jul 11:33:02 - [warn] [bp-modbus-client:9d1a5f85a60e2b64] Modbus initialized  
Jul 26 11:33:02 raspberrypi Node-RED[596]: 26 Jul 11:33:02 - [info] Started flows  
Jul 26 11:33:02 raspberrypi Node-RED[596]: 26 Jul 11:33:02 - [info] [serialconfig:b4914f5df746ca22] serial port /dev/ttyAMA0 opened at 4800 baud 8N1

---

<div class="post-metadata">

**Author:** ![Colin](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/colin/32/17040_2.png) [@Colin](https://discourse.nodered.org/u/Colin)\
**Post date:** [26 July 2023 08:05 UTC](https://discourse.nodered.org/t/usb-rs485-rpi4b-connection-issue/80066/2 "2023-07-26T08:05:21Z")

</div>

> [@DrdP](#):
>
> I am trying to read info from a RS485 soil sensor.

Are you using an rs485 adaptor to connect the device to the pi?

---

<div class="post-metadata">

**Author:** ![DrdP](https://avatars.discourse-cdn.com/v4/letter/d/b5ac83/32.png) [@DrdP](https://discourse.nodered.org/u/DrdP)\
**Post date:** [26 July 2023 19:46 UTC](https://discourse.nodered.org/t/usb-rs485-rpi4b-connection-issue/80066/3 "2023-07-26T19:46:41Z")

</div>

I am using a Digitech XC-4136 USB to RS485 converter

---

<div class="post-metadata">

**Author:** ![Colin](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/colin/32/17040_2.png) [@Colin](https://discourse.nodered.org/u/Colin)\
**Post date:** [26 July 2023 20:17 UTC](https://discourse.nodered.org/t/usb-rs485-rpi4b-connection-issue/80066/4 "2023-07-26T20:17:49Z")

</div>

Select the nodes you are using to test the read operation and Export them here. Export only as much of the flow as is necessary to show how you are trying to communicate with it.

Also point us to the documentation for the device so we can check it out.

I notice that you are using an old version of node-red, it would probably be worth while updating to the latest.

---

<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/1X/d073cd938eafa2e558d7c2cd59003b3ef4963033.png) [@system](https://discourse.nodered.org/u/system)\
**Post date:** [24 September 2023 20:18 UTC](https://discourse.nodered.org/t/usb-rs485-rpi4b-connection-issue/80066/5 "2023-09-24T20:18:40Z")

</div>

This topic was automatically closed 60 days after the last reply. New replies are no longer allowed.