Endress+Hauser alpha-log Betriebsanleitung Seite 47

The serial interface is produced as an intrumentation
interface. Connection to the level of office data handling
is not permitted.
3.9 The transmission protocol of the interfaces
Serial interface: RS232 or RS485/RS 422
Data bits: 7
Parity: even
Stop bits: 1
Protocol: SOH unit address STX data ETX BCC
Unit address: '0"0'..'9''9 presettable in the unit
BCC: Exclusive OR combination of all data including
ETX. On wrong or faulty BCC the unit answers with a
NAK and returns to its basic condition "Wait for SOH".
Example:
ASCII: SOH 0 1 STX R 9 8 3 ETX BCC
decimal: 1 48 49 2 82 57 56 51 3 99
BCC = 82 XOR 57 XOR 56 XOR 51 XOR 3 = 99
(ASCII: c)
The unit also returns to its base condition "Wait for
SOH" on all other transmission faults, (eg. Parity error,
protocol error etc.). The receive "Time out" time
between two characters is one second.
The recorder only operates in slave mode, this means it
only transmits data on command from the master. The
slave answers with its own unit address.
Maximum data length is 41.
3 Installation/connection/setting up
45