# MODBUS RS485 Sensor read
**URL:** https://discourse.nodered.org/t/modbus-rs485-sensor-read/83399
**Category:** General
**Tags:** modbus
**Created:** [3 December 2023 10:06 UTC](https://discourse.nodered.org/t/modbus-rs485-sensor-read/83399 "2023-12-03T10:06:03Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@gumue](https://discourse.nodered.org/u/gumue)
#### Post date: [3 December 2023 10:06 UTC](https://discourse.nodered.org/t/modbus-rs485-sensor-read/83399/1 "2023-12-03T10:06:03Z")
I am not familiar with Modbus RTU / RS485, but I need to integrate a multi-parameter sensor in Node-Red flow that can be read out with Modbus RTU. In the supplied sensor software I can record a log of the communication via an RS485 USB adapter on the PC - it looks like this:
T→ 01 03 01 00 00 70 45 D2 length=8
R← 01 03 E0 AA 53 A1 41 FF FF FF FF 3F FF FF FF FF FF 3F 00 00 00 00 00 66 A6 CA 42 52 49 1D 3A 52 49 1D 3A 00 00 00 00 00 00 00 00 00 00 01 8B 79 44 55 55 D5 3F 4C 8C 3B 40 DE 3E 71 43 FB EF 83 43 40 75 8D 3F 93 9A 9B 3F FF FF FF FF 3F D2 44 FC 40 08 E0 AB 42 FF FF FF FF FF 3F FF FF FF FF FF FF 3F FF FF FF FF FF FF 3F FF FF FF FF FF FF 3F FF FF FF FF FF 3F FF FF FF FF FF 3F FF FF FF FF 3F FF FF FF FF 3F FF FF FF FF 3F FF FF FF FF FF 3F FF FF FF FF 3F 55 A4 04 3F FF FF FF FF FF FF 3F FF FF FF FF FF FF 3F FF FF FF FF FF FF 3F FF FF FF FF FF FF 3F FF FF FF FF FF FF 3F FF FF FF FF FF FF 3F FF FF FF FF FF FF 3F FF FF FF FF FF 3F FF FF FF FF 3F FF FF FF FF 3F FF FF FF FF 3F FF FF FF FF 3F FF FF FF FF 3F FF FF FF FF 3F FF FF FF FF 3F FF FF FF FF 3F FF FF FF FF 3F FF FF FF FF 3F C5 C2 length=229
Unfortunately, I don't understand how to read this data into individual values in Nodered - I hope you can help me here with an example flow, for example.
Thank you!
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### Author:  [@Steve-Mcl](https://discourse.nodered.org/u/Steve-Mcl)
#### Post date: [3 December 2023 10:36 UTC](https://discourse.nodered.org/t/modbus-rs485-sensor-read/83399/2 "2023-12-03T10:36:24Z")
Have you installed `node-red-contrib-modbus`?
Have you managed to communicate with the device?
What are you expecting the values to look like? (i.e. is there a document explaining what the values format are?)
* * *
NOTE:
That `t →` data means Transmit:
The data `01 03 01 00 00 70 45` is a Modbus packet and is decoded as:
| Part of Data Package | Description | Value |
| --- | --- | --- |
| 01 | Slave address | 0x01 (1) |
| 03 | Function code | 0x03 (3) - Read Holding Registers |
| 01 00 | Starting address | Physical: 0x0100 (256) |
| | | Logical: 0x0101 (257) |
| 00 70 | Quantity | 0x0070 (112) |
| 45 D2 | CRC | 0x45D2 (17874) |
See for your self: [Online Modbus RTU Parser & Modbus TCP Parser](https://rapidscada.net/modbus/)
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### Author:  [@system](https://discourse.nodered.org/u/system)
#### Post date: [1 February 2024 10:36 UTC](https://discourse.nodered.org/t/modbus-rs485-sensor-read/83399/3 "2024-02-01T10:36:43Z")
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