Ecotech Acoem Serinus 30 - Appendix C. Bayern-Hessen Protocol; C.1 Command Format

Serinus® 30 User Manual 3.3
Page 218
Appendix C. Bayern-Hessen Protocol
The Serinus implements a limited subset of the Bayern-Hessen Network protocol. Only the ability to
set the instrument calibration state (measure, span or zero) and read the gas concentrations are
supported.
C.1 Command Format
<STX><text><ETX>< bcc1><bcc2>
Where:
<STX> ASCII Start of Text = 0x02 hex.
<Text> ASCII text maximum length of 160 characters.
<ETX> ASCII End of Text = 0x03 hex.
<bcc1> ASCII representation of block check value MSB. (That is, the character
“3” for 3, the character “F” for 15, etc.)
<bcc2> ASCII representation of block check value LSB.
The block check algorithm begins with 0 and exclusive-OR’s each ASCII character from <STX> to <ETX>
inclusive. This block check value is converted to ASCII format and sent after the <ETX> character.
Examples
This is an example of a valid Bayern-Hessen data request for an instrument that has a Serial ID of 97
(Serial ID assigned in the Main Menu → Communications Menu → Serial Communication Menu):
<STX>DA097<EXT>3A
The block check calculation is best shown by the following example:
Table 34 – Bayern-Hessen Data
Character
Hex Value
Binary
Block Check
<STX>
02
0000 0010
0000 0010
D
44
0100 0100
0100 0110
A
41
0100 0001
0000 0111
0
30
0011 0000
0011 0111
9
39
0011 1001
0000 1110
7
37
0011 0111
0011 1001
<ETX>
03
0000 0011
0011 1010
The binary value 0011 1010 corresponds to the hex value 3A. This value in ASCII forms the last two
characters of the data request message.