Temperature Indicator : 409-4IN
REF NO: m47/om/201
Issue NO: 04
Page 25 of 34
8.
Communication Parameter
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
03
Read Holding registers
Use to read PV
04
Read input registers
Use to read programmable registers
05
Force single coil
Use to ON /OFF single coil.
16
Preset Multiple register
Use to write programmable register
Table 11.
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.
8.1.1 Parameter Address Details For
Mtyp
:
A
Sr.No
Parameter
Absolute
address
Type
Minim
um
value
Maximu
m
Value
Access
Type
1.
*Relay status1
1
Bit
0
1
R/W
2.
*Relay status2
2
Bit
0
1
R
3.
*Alarm status1
10001
Bit
0
1
R
4.
*Alarm status2
10002
Bit
0
1
R
5.
*Alarm 1 Blinking
10004
Bit
0
1
R
6.
*Alarm 2 Blinking
10005
Bit
0
1
R
7.
Process value
30001
Integer
R
8.
Ambient
30002
Integer
R
9.
Zero display
40001
Integer
R/W
