Appendix Ⅳ Modbus; Modbus Protocal Outline; Data Type - Sinexcel SVG 100 Ultra User Manual

APPENDIX Ⅳ MODBUS

MODBUS PROTOCAL OUTLINE

Protocal Overview
MODBUS is an application layer protocol and widely used in industrial control. It is the de facto industry
standard. This protocol describes the MODBUS communication protocol implemented in Sinexcle product
family. Communication uses response mode, the host sends request, then the slave to execute request and
response.
Application Scope
This protocol applies to SVG series product, for DSP module data exchange with monitor and for monitor data
exchange with background software.
Reference Standard
MODBUS RTU communication protocol standards
Based level communication protocol
Asynchronous serial protocol UART
Physical interface
Two-wire RS485 interface
Data transfer rate
Optional between 9600/19200/38400bps, default is 19200bps.
Character format
The transfer mode is asynchronous mode; half duplex mode; start bit contains 1 bit; data bit contains 8 bits;
stop bit contains 1 bit; no check.

DATA TYPE

Integer
Integer storage format is 2 bytes. When transmitting, high bytes D15~D8 go first, and then low bytes D7~D0.
Float
57