Model: LC5296 Dual Channel Temperature Controller
Doc. Ref. no.:- m61C/om/101
Issue no. 01D/ENGG-114
User’s Manual
Page 25 of 30
9. COMMUNICATION PROTOCOL
–MODBUS RTU
9.1 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
CODE
NAME
Function
01
Read coil status
Use to read Relay and Digital output status
03
Read Holding registers
Use to read PV, Control, RSP output etc
04
Read input registers
Use to read programmable registers
06
Preset Single register
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.
9.2 Parameter Address Details
Sr.
No.
Parameters
Absolute
Address
Type
Access
Type
1
PROCESS VALUE-1
30001
Int
Read
Only
2
PROCESS VALUE-2
30002
Int
Read
Only
3
RELAY-1 STATUS
30003
Int
Read
Only
4
RELAY-2 STATUS
30004
Int
Read
Only
NOTE:
Process Value (PV) Error Conditions Value
OPEN
:
32767
UNDER
:
32765
OVER
:
32766
Sr.
No.
Parameters
Absolute
Address
Type
Access
Type
1
Input Type
40001
Int
R + W
2
Zero
40002
Int
R + W
3
Span
40003
Int
R + W
4
SET Type-1
40004
Int
R + W
5
SET Type-2
40005
Int
R + W
6
Open Sensor Status
40006
Int
R + W
7
Decimal Point
40007
Int
R + W
8
Display set point
40008
Int
R + W
9
Brightness
40009
Int
R + W
10
Serial Number
40010
Int
R + W
