LARTET DC-24S, Руководство пользователя

Страница: 30 / 41

4-10 COMMUNICATION PROTOCOLS CHAPTER 4
DC-24 and DC-25 operation manual
4.5. ModBus/TCP PROTOCOL
The frame must accomplish the ModBus/TC specifications for being accepted by the
display.
4.5.1. Modbus/TCP protocol
End of block is not necessary.
Local Port = 502.
4.5.2. Read data from the display
To read the current temperature and humidity, the functions 03h or 10h must be used.
The blocks are the following
Function 03h.
The temperature is in register 40003 (address 02h) and the humidity in the register
40004 (address 03h)
Read temperature:
Identifier Protocol
Number of
bytes
Unit Function
Start
address
Number of
registers
08h 62h 00h 00h 00h 06h 01h 03h 00h 02h 00h 01h
Response from the display
The response frame from the display is the following.
In this example, the identifier is 0862h and the read temperature is 20.5ºC = CDh
Identifier Protocol
Number of
bytes
Unit Function
Number of
registers
Data
08h 62h 00h 00h 00h 05h 01h 03h 02h 00h CDh
Read temperature and humidity
Temperature and humidity can be read reading 2 registers from the register 40003.
In this example, the identifier is 0618h, the read temperature is 20.5ºC (CDh) and the humidity
is 42% (1Ah)
Sent frame:
Identifier Protocol
Number of
bytes
Unit Function
Start
address
Number of
registers
06h 18h 00h 00h 00h 06h 01h 03h 00h 02h 00h 02h
Response from the display
Identifier Protocol
Number
of bytes
Unit Function
Number of
registers
Data
06h 18h 00h 00h 00h 07h 01h 03h 04h 00h CDh 00h 2Ah