SUPMEA SUP-PTU300, Руководство пользователя

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Chapter 3 Data interface
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Chapter 3 Data interface
3.1 Overview
SUP-PTU300 turbidity meter supports two standard data interfaces
simultaneously :485 Modbus interface and 4-20 mA interface. Users can choose
any kind of use according to their own needs.
3.2 485Modbus interface
3.2.1 Wiring mode
485Modbus interface wiring mode as below table.
Color Function
Green 485A
Yellow 485B
3.2.2 485 baud rate
485Modbus interface baud rate is 9600, data bit 8, no check, stop bit :1.
3.2.3 Modbus Agreement
1.Host call format:
host sends a read command to the turbidity sensor in 8 bytes in the following
format (MSB first):
MSB LSB
byte 1 byte 2 byte 3 byte 4 byte 5 byte 6 byte 7 byte 8
Meaning:
byte 1: turbidity sensor ID number with value range 0 x01-0xFF, default value 0
x03;.
byte 2: Modbus the function code in the protocol, should fill in 0 x03( read);
byte 3, byte 4: register start address, high byte in byte 3, low byte in byte 4;