# 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](https://docs.yudash.com/device-to-cloud-api/industrial-protocols/modbus) documentation.

## Modbus/RS485 interfacing example

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

<figure><img src="https://1858257737-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FToww5EM1cml3ouN6fvnJ%2Fuploads%2FMLRFUEf8g02sid35HLvS%2F10.jpg?alt=media&#x26;token=468bb2ee-7665-48eb-b308-eec8fc5910e7" 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="https://1858257737-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FToww5EM1cml3ouN6fvnJ%2Fuploads%2F60U5dIKuYDsLcDQ0YGWR%2F11.jpg?alt=media&#x26;token=868fb09c-be2b-48de-8810-4d5de8c64fe4" alt=""><figcaption></figcaption></figure>