Teledyne 300M instruction manual Viewing and Modifying Variables, 7-11

Teledyne API Model 300M CO Analyzer Instruction Manual, 04033, Rev. A

7.6 Viewing and Modifying Variables

The most powerful feature of the RS-232 interface is the ability of a host computer to view and modify the analyzer's internal variables. Just as the operator modifies the variables by means of the setup mode, the host computer modifies them by means of the RS-232 interface.

To view a variable's value, the host computer issues a command of the following format:

V VARIABLE<CRLF>

The CPU will respond by sending a message of the following format to the RS-232 output:

V VARIABLE=VALUE WARNLO WARNHI <DATALO-DATAHI> <CRLF>

In both cases "VARIABLE" is the name of the variable that is being viewed. "VALUE" is the current value of the variable. "WARNLO" and "WARNHI" are the low and high warning limits, respectively, but may not appear for all variables since some variables do not have warning limits. "DATALO" and "DATAHI" are the low and high data entry limits, respectively, and are given for all variables. The CPU will not set a variable's value or warning limits to values that are outside of the data entry limits.

For example, to see the optical bench temperature set point, the host computer would issue the command:

V BENCH_SET<CRLF>

the CPU would respond with something like:

V DDD:HH:MM IIII BENCH_SET=50 45 55 <0-100> <CRLF>

indicating that the current set point is 50 degrees, the warning limits are 45 to 55 degrees, and the data entry limits are 0 to 100 degrees.

To modify a variable's value, almost the same format of command is used:

V VARIABLE=VALUE WARNLO WARNHI<CRLF>

The "VARIABLE" field is the name of the variable being modified, and the "VALUE" field is the new value. "WARNLO" and "WARNHI" are the low and high warning limits, respectively, and may only be given if the variable uses warning limits. They are optional for variables that use warning limits and, if not given, the warning limits are not changed.

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