Laurel Electronics LTM DPM SERIES ANALOG INPUT, SERIAL DATA OUTPUT User Manual
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6.0 SUPPORTED EXCEPTION RESPONSE CODES
Code
Name
Error Description
---- -------------------- ------------------------------------------------------
01
Illegal Function
Illegal Function Code for this Slave. Only hex Function
Codes 03, 04, 05, 08, 10 (dec 16) are allowed.
02
Illegal Data Address Illegal Register Address for this Slave.
03
Illegal Data Value Illegal data value or data length for the Modbus protocol.
04
Slave Device Failure Slave device failure (eg. Transmitter set for external gate).
7.0 MESSAGE FORMATTING
MA = Meter Address
DD = Data (Hex)
CL = CRC Lo Byte
FC = Function Code
WW = Data (On/Off)
CH = CRC Hi Byte
RA = Register Address
SF = Sub-Function
CR = Carriage Return
NR = Number of Registers
EC = Error Code
LF = Line Feed
NB = Number of bytes
LRC = ASCII Checksum
Modbus RTU Format
Byte Number
FC
Action
> 3.5
Char
1
2
3
4
5
6
7
8
9
10
11
03
03
Request
Response
NoTx
NoTx
MA
MA
FC
FC
RA
NB
RA
DD*
NR
DD*
NR
CL
CL
CH
CH
04
04
Request
Response
NoTx
NoTx
MA
MA
FC
FC
RA
NB
RA
DD*
NR
DD*
NR
CL
CL
CH
CH
05
05
Request
Response
NoTx
NoTx
MA
MA
FC
FC
RA
RA
RA
RA
WW
WW
WW
WW
CL
CL
CH
CH
08
08
Request
Response
NoTx
NoTx
MA
MA
FC
FC
SF
SF
SF
SF
WW
DD
WW
DD
CL
CL
CH
CH
10
10
Request
Response
NoTx
NoTx
MA
MA
FC
FC
RA
RA
RA
RA
NR
NR
NR
NR
NB
CL
DD*
CH
DD* CL CH
Exception
Response
NoTx
MA FC
+80
EC
CL CH
DD* = (DD DD) times NR (Number of Registers)