Instruction Manual
748441-D
April 2002
4-4 Serial Interface Option
Rosemount Analytical Inc. A Division of Emerson Process Management
Model CAT100
4-4 STRING SYNTAX
Start Character (“$” = Hex 24)
If the start character is missing, this will result
in transmission of the correspond status string
by the analyzer.
Terminate Character (“CR” = Hex OD)
If the terminate character is missing, no de-
coding of the transmitted information will be
performed and the analyzer will not respond.
No response message will be transmitted.
Instruction Code
Each instruction is assigned a unique three-
digit instruction code. If a received instruction
code should be other than three digits in
length or contain non-numerical ASCII charac-
ters, the analyzer will transmit an appropriate
status string. Reception of unassigned instruc-
tion codes will also result in the transmittal of
a status string.
In the RS232C mode of operation, the instruc-
tion code immediately follows the start charac-
ter. In the RS485 mode of operation, the start
character is followed by a two-digit device
identification code, the separator character “;”
and a three-digit instruction code, in that or-
der.
Hyphen Character (“;” = Hex 3B)
Individual elements of a string line are sepa-
rated by the hyphen character. Missing hy-
phen characters can lead to misinterpretations
of the strings, and will result in transmission of
a corresponding status string.
