Kipp&Zonen COMBILOG Data Logger - Manual (Page 109)

FCS: Frame-Check-Sequence (length = 2 byte):
The Frame-Check-Sequence FCS identifies the running digital
sum of the telegram. This is the sum of the ASCII-values in the
telegram modulo 256. It is calculated in the ASCII-protocol from
Start-Delimiter (SD), Destination Address (DA) and Data-Unit:
CheckSum_ASCII = [SD+DA+DataUnit] mod 256. In the ASCII-
protocol the value is given as a two-digit ASCII-string (ASCII
"00"..."FF").
ED: End-Delimiter (length = 1 byte):
The End-Delimiter ED identifies the end of the telegram. In an
ASCII-protocol it has the value hex 0D ("Cr").
ACK: Acknowledge (length = 1 byte):
With a request, where no data are returned, the correct execu-
tion of the instruction is acknowledged by an "Acknowledge"-
character (hex 06).
NAK: No-Acknowledge (length = 1 byte):
When a request has not been performed correctly, a "No Ac-
knowledge" (hex 15) is sent back.
Hardware Manual COMBILOG 1022
109