Contents
INTRODUCTION
1
1 GENERAL
2
1.1 RS-232C Communications Interface
1.2 RS-422A/485 Communications Interface
2
COMMUNICATIONS PARAMETERS
2
3 SETTINGS OF SWITCHES
3
3.1 Instrument number
3.2 Communications port
3.3 Communications type
4 CONNECTIONS
4
4.1 Connection Precautions
4.2 Communications Cables
4.3 RS-232C Connections
4.4 RS-422A/485 Connections
5
MODBUS PROTOCOL
11
5.1 Message Transmission Modes
5.2 Data Time Interval
5.3 Message Configuration
5.4 Creating a Message
5.5 Function Code
5.6 Processing in Abnormal Status
5.7 Table of Reference
5.8 Range number list
6
SAMPLE PROGRAM (For RTU Protocol)
50
