# Encapsulated Modbus RTU

**URL:** https://discourse.nodered.org/t/encapsulated-modbus-rtu/3319
**Category:** General
**Created:** [21 September 2018 07:19 UTC](https://discourse.nodered.org/t/encapsulated-modbus-rtu/3319 "2018-09-21T07:19:11Z")
**Posts on this page:** 3
**Page:** 1

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### Author: ![88bit](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/88bit/32/79334_2.png) [@88bit](https://discourse.nodered.org/u/88bit)
#### Post date: [21 September 2018 07:19 UTC](https://discourse.nodered.org/t/encapsulated-modbus-rtu/3319/1 "2018-09-21T07:19:11Z")

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Hi I need a little help, I have a device which outputs Modbus over RS 485. I use a Modbus to Ethernet converter which encapsulates the Modbus data into an Ethernet packet.  
I use the amassing node-red-contrib-modbus nodes. However I struggle to make any progress to de-capsulate the packets. Is this possible with this nodes?

Thank you for your help

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### Author: ![mtoko](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/mtoko/32/138_2.png) [@mtoko](https://discourse.nodered.org/u/mtoko)
#### Post date: [21 September 2018 15:47 UTC](https://discourse.nodered.org/t/encapsulated-modbus-rtu/3319/2 "2018-09-21T15:47:23Z")

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You don't mention what hardware you are using, but I have had success using the RS485 and node-red-contrib-modbus directly with a USB to RS485 adapter on a Raspberry Pi, the converter would not be needed. The key issue is to understand the modbus registers the device outputs.

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### Author: ![88bit](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/88bit/32/79334_2.png) [@88bit](https://discourse.nodered.org/u/88bit)
#### Post date: [22 September 2018 02:10 UTC](https://discourse.nodered.org/t/encapsulated-modbus-rtu/3319/3 "2018-09-22T02:10:57Z")

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I'm using a USR-TCP232-304 RS485 Eternet converter. This device encapsulates the Modbus 485 signal from the PLC i'm using into a TCP packet. There is a difference between devices which naively support Modbus TCP and these converts. I use SCADA BR (now SCADA LTS) and can read the Modbus from the PLC fine via TCP. This application has an option 'ENCAPSULATED'.

Here is a discussion but I don't understand the bit with 'added to the main branch'  
[https://github.com/stephane/libmodbus/issues/192](https://github.com/stephane/libmodbus/issues/192)

Thanks for helping out.