Specifications

37
Schneider Electric
Guide to Integration
Review 40
Networks 40
Systems 40
Bauds and bits per second 40
Architectures 41
The 20 mA current loop 42
The RS232 link 43
RS485 link 47
Standards EIA 485A (March 98 update) 48
and TSB89 (application guidelines for TIA/EIA-485-A) 48
Interfaces 50
RS232/RS485 50
Modems 51
The Modbus Protocol 56
Difference between ASCII and RTU frames 56
Differences between Modbus and Modbus+ protocols 56
Modbus / Jbus 56
Description of exchanges 58
Principles used 60
Addressing 61
Functions 61
Control of messages received by the slave 62
Algorithm for generating CRC16 75
Schneider Specifications 79
Overview 79
Connection 83
Components available 84
Summary 85
Specific Characteristics of Products 86