Serial Communications
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SERIAL COMMUNICATIONS
Communication Protocol
Communication with all analyzers through the RS-485 connection uses
the following word format:
8 data bits
1 stop bit
No Parity
In addition, the baud rate is fixed at 9600bps.
The communication protocol is a basic master/slave, command/response
protocol. The master initiates each communication transfer. There is one
master on the communication line, but there can be multiple sensors act-
ing as slaves. Up to 32 sensors can be connected on one network.
Command Message Format
The command message format is as follows:
Start Character
Node Address
Command Letter
Data
Checksum
End Character
“>” (ASCII charac-
ter 3E Hex)
2 Hex ASCII char-
acters (00 to FF)
(See Command
Section for list of
commands)
(n characters -
depends on com-
mand)
2 hex ASCII char-
acters (sum of all
preceding charac-
ters except the “>”
character)
Carriage Return
(ASCII character
0D Hex)
