Hardware Manual COMBILOG 1020
131
Note:
In the MODBUS-protocol T
2max
is at least
2 msec. The values for T
2min
and T
3max
and the behaviour of the
datalogger if the time T
3max
is exceeded (communication timeout,
see also chapter 5.8, error handling) can be adjusted by means
of the configuration software
COMBILOG.EXE
. The default val-
ues for T
2min
is 1 CT and for T
3max
60 sec.
11.8.2
Telegram Format
The request and response telegrams in the RTU-mode used by
the sensor modules start with an idle-interval of at least 3.5 char-
acter lengths. The simplest way of attaining this is by waiting for
at least 4 character-times after receiving the last character of a
telegram. The telegrams have no Start-Delimiter and no End-
Delimiter either. The first field after that idle-interval is the ISM-
Address (ADR) followed by the function number (FNR) and the
function parameters or data respectively. At the end the tele-
grams contain a check sum (CRC) with a length of 16 bits. The
check sum is calculated from the whole telegram without the CRC
itself. The CRC-polynom is: u
15
+ u
13
+ 1. The start value is hex
FFFF.
request telegram
idle interval ADR
FNR
function parameters / data CRC
> 3,5 CT
1 byte 1 byte n byte
2 byte
response telegram
idle interval ADR
FNR
function parameters / data CRC
> 3,5 CT
1 byte 1 byte n byte
2 byte
Summary of Contents for COMBILOG 1020
Page 1: ...COMBILOG 1020 Datalogger Hardware Manual Version 3 09...
Page 2: ...Hardware Manual COMBILOG 1020 2 Issue 03 11 2005 Technical data are subject to change...
Page 4: ...Hardware Manual COMBILOG 1020 4...
Page 6: ...Hardware Manual COMBILOG 1020 6...
Page 12: ...Hardware Manual COMBILOG 1020 12...
Page 86: ...Hardware Manual COMBILOG 1020 86 Bild 8 1 Example Master Slave System...
Page 169: ...Hardware Manual COMBILOG 1020 169...
Page 170: ...Hardware Manual COMBILOG 1020 170...