INFICON T-Guard Leak Detection Sensor Interface description - Manual (Page 5)

RS232 ASCII Interface Protocol
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2 RS232 ASCII Interface Protocol
The RS232 ASCII protocol is similar to the SCPI, a standard protocol widely used for
measurement equipment.
2.1 Communication Parameters
2.2 Command Format
In ASCII mode any command starts with “ * “ (ASCII code 42 dec) and is finished with
CR+LF. There is no differentiation between upper and lower case. A blank is required
between the command and the parameter, no other blanks are allowed.
There is a short and an extended form of the command. Either the short or the
extended command must be used, no other abbreviations are allowed. Command
words have to be separated by a colon.
In chapter
2.3 „ List of ASCII Commands ” short and extended command are specified
by upper and lower case. Example: "* STATus" means that the extended command
version is "* STATUS" and the short command version is "* STAT“.
A command can be composed of up to three words. Parameters have to be
separated by commas.
Each command is answered with „OK“ or „EXX“ (in case of an error). For a list of all
error message see section
2.3.1 . The transmission can be cancelled with ESC
(ASCII code 27dec), ^C (ASCII code 3 dec) or ^X (ASCII code 24 dec).
Some commands can be used as queries, some can be used to set parameters and
some can be used for both. A query is marked by a “ ? “ (ASCII code 63 dec) after
the command, for setting data the command has to be followed by the parameter.
Parameters can be boolean or numerical:
Notice Always use a point as the decimal marker. If a comma is used during
numerical data entry, the conversion of the number is cancelled at this
point and only the integer part of the number will be used.
The following table lists all commands available in the ASCII mode.
Notice After sending a command from the PC to the leak detector, the PC must
wait for the answer from the leak detector before sending a new command.
The PC should wait at least 1500 ms for the answer before retrying.
Notice A blank is required between the command and the parameter, no other
blanks are allowed. Replace blanks in names by underscores.
Data Format
baudrate
19,200 or 9,600
data bits 8
parity none
stop bits 1
flow control none
Boolean 0 / 1 or OFF / ON Or ENAble / DISAble
Numeric representation format: integer, real (15.6) or exponential (4.5E-7)
Format: [space] [sign] [ddd] [.] [ddd] [e[sign]ddd] (d: digit)