Pneumercator MODBUS RTU RS-485 - MODBUS Function Format

MODBUS RTU Instruction Manual - 2017-11-02.docx Page 7 of 14 November 2, 2017
2.0 MODBUS Function Format
Function Code 3: Read Holding Registers
Note: All Queries are in Hex RTU format
Master to Slave (TMS/LC2000) Query – Read TMS/LC2000 Data
Slave (TMS/LC2000) to Master Response – Read TMS/LC2000 Data
FCSLA STA
56781234
NPR EC
Error Check - 16-bit CRC
Number of Points to Read
Start Address
Function Code (03H)
Slave
A
ddress (00H - 0FH)
CHAR #
FCSLA BC DATA EC
Error Check - 16-bit CRC
Data Stream
Byte Count
Function Code (03H)
Slave
A
ddress (00H - 0FH)
BC+3 BC+4 BC+51234CHAR #