Model: LC5296-AT /LC5248E-AT/LC5296V-AT masibus
Doc. Ref. no. : - m61C/om/301
Issue no. 13
User’s Manual Page 37 of 44
10. COMMUNICATION PROTOCOL–MODBUS RTU
10.1 Introduction
The unit can be connected in RS-485 communication data link either in multi drop or
repeat mode. Each unit must have unique Serial Number. Entire range of addresses (1 to
247) may be used. Before starting any communication, choose a baud rate compatible to
the host computer. The serial protocol used is MODBUS RTU.
Function Code for Modbus
Use to read Relay and Digital output status
Use to read PV, Control, RSP output etc
Use to read programmable registers
Use to write programmable register
The error checking field contains a 16-bit value implemented as two eight-bit bytes. The
error check value is the result of a Cyclical Redundancy Check (CRC) calculation
performed on the message contents.
10.2 Parameter Address Details
NOTE:Process Value (PV) Error Conditions Value
OPEN : 32767
UNDER : 32765
OVER : 32766