Read Modbus data

Use ModbusDoctor to easily test the system → https://www.kscada.com/modbusdoctor.html

Configuration

TCP/IP IP address is µWiotys IP address Numport : 502 - Timeout : 1000.

To read Modbus device previously configured, select your slave number in modbus doctor.

Get device configuration

Address

Size

Description

Type

Address

Size

Description

Type

0x0000

1

Modbus dictionary's version

uint16

0x0001

4

Device EUI

uint64

0x0005

1

Device Wi6labs reference ID

uint16

What you can see on Modbus Doctor:

 

read_config_modbus5.png
register 0x05h length 0x08h

Get device Value

Address

Size

Description

Unit

Data Type

Address

Size

Description

Unit

Data Type

0x1000

2

last payload timestamp

second

U32

0x1002

1

Temperature 0

Celsius / 10

S16

0x1003

1

Humidity 0

% from 0 to 100

U16

What you can see on Modbus Doctor:

 

read_thr_modbus5.png
register 0x1000h length 0x05h

Real values:

Timestamps = 0x5FCDCF36 (word swapping) = 1 607 323 446 seconds = 7/12/2020 6:44:06
(check https://www.epochconverter.com/ for conversion example)

Temperature = 0xDE = 222 Celsius/10 = 22,2 °C

Humidity = 0x21 = 33 % of Humidity