# Modbus RS485

Modbus/RS485 is a popular serial protocol to read various sensors. YuDash NUREX is being used to read a variety of instruments, sensors and PLCs for various applications. NUREX provides easy to configure approach for reading field Modbus instruments. Following are the key information points required for a successful read of instrument through Modbus:

1. Baudrate
2. Data Bits, Parity and Stop Bit
3. Slave ID of instrument
4. Modbus register information to read:
   1. Modbus register numbers and types)
   2. Modbus register data types (Size: integer/float/real. Byte swapping information: LSB/MSB etc.)
5. Modbus register address.

## Modbus Register Mapping in YuDash NUREX. <a href="#h.jt0n9eorg4hg_l" id="h.jt0n9eorg4hg_l"></a>

Various Modbus topologies are covered in [Modbus protocol](/device-to-cloud-api/industrial-protocols/modbus.md) documentation.

## Modbus/RS485 interfacing example

YuDash NUREX datalogger is connected with Selec EM2M energy meter on Modbus channel#1&#x20;

<figure><img src="/files/CtvYlgH1dcssErpYulJh" alt=""><figcaption></figcaption></figure>

## Modbus/RS485 interfacing example (2channels)

YuDash NUREX datalogger is connected with Selec EM2M energy meter on Modbus channel#1 and XY-02 temperature and humidity sensor on Modbus Channel#2.

<figure><img src="/files/fj1jn9QdrSmaoKZSiFgS" alt=""><figcaption></figcaption></figure>


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.yudash.com/nurex/um/modbus.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.