Kipp&Zonen COMBILOG Data Logger - Manual (Page 107)

11.6 ASCII protocol
11.6.1 Telegram Format for the ASCII Protocol
For the request-and response telegrams the ASCII-protocol
distinguishes between telegrams without and with check sum.
The telegrams are characterized with different start-delimiters
(SD). A request telegram without a check sum will lead to a re-
sponse telegram which also contains no check sum. The same
applies to for requests with check sum, accordingly. Further-
more there are two short telegrams with the length of one char-
acter each to perform a positive or negative acknowledgement.
SD DA ReqDataUnit ED
1 2 n
n+4 characters
request telegram without checksum:
1
SD ResDataUnit ED
1 n
n+2 characters
1
response telegram without checksum:
SD DA ReqDataUnit ED
1 2 n 2
n+6 characters
request telegram with check sum:
FCS
1
SD ResDataUnit ED
1 n 2
n+4 characters
response telegram with checksum:
FCS
1
ACK
1 character
Positive Acknowledge
NAK
1 character
Negative Acknowledge
Hardware Manual COMBILOG 1022
107