Laurel Electronics LTM CTR SERIES PULSE, AC or PROCESS TOTALIZER INPUT, SERIAL DATA OUTPUT User Manual
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Modbus ASCII Format
Byte Number
FC
Action
1
2
3
4
5
6
7
8
9
10
11
12
13
03
03
Request
Response
:
:
MA
MA
FC
FC
RA
NB
RA
DD*
NR
DD*
NR
LRC
LRC
CR
CR
LF
LF
04
04
Request
Response
:
:
MA
MA
FC
FC
RA
NB
RA
DD*
NR
DD*
NR
LRC
LRC
CR
CR
LF
LF
05
05
Request
Response
:
:
MA
MA
FC
FC
RA
RA
RA
RA
WW
WW
WW
WW
LRC
LRC
CR
CR
LF
LF
08
08
Request
Response
:
:
MA
MA
FC
FC
SF
SF
SF
SF
WW
DD
WW
DD
LRC
LRC
CR
CR
LF
LF
10
10
Request
Response
:
:
MA
MA
FC
FC
RA
RA
RA
RA
NR
NR
NR
NR
NB
LRC
DD*
CR
DD*
LF
LRC CR
LF
Exception
Response
:
MA FC
+80
EC LRC CR
LF
DD* = (DD DD) times NR (Number of Registers)
8.0 MESSAGE EXAMPLES
All examples are for Transmitter Address = 01 and No Parity.
Ser_4 ->
Addr ->
Action
Modbus RTU
010
001
Modbus ASCII
020
001
Restart Com-
munications
Request
Response*
010800010000B1CB
010800010000B1CB
:010800010000F6crlf
:010800010000F6crlf
Meter Reset
Request
Response
01050001FF00DDFA
None
:01050001FF00FAcrlf
None
Digital Reading
** ***
Request
Response
01040003000281CB
010404000009D67C4A
:010400030002F6crlf
:010404000009D618crlf
Write Setpoint
1 = +37.00***
Request
Response
0110000100020400000E743624
01030400000E74FE74
:0110000100020400000E7466crlf
:011000010002ECcrlf
Read Setpoint
1 = +37.00***
Request
Response
01030001000295CB
01030400000E74FE74
:010300010002F9crlf
:01030400000E7476crlf
* Suggested as first message after power-up. If transmitter is in Listen-Only mode, no response
is returned. ** Example while reading +25.18 *** Decimal point is ignored.
9.0 INTERNAL REGISTERS: Please refer to the full Modbus Protocol Communications Manual,
which is downloadable from our website.