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LIMIT PROGRAMS
The programs [MHI TOR and LOG give you the option to call a user-written limit program as one of the
available limit actions.
Limit programs may be used to perform specific actions that are not offered by
the main program, such as controlling another instrument, or switching several actuators. Limit programs
are written as BASIC subprograms.
There are two classes of limit activities: transition events, and continuous events. A transition event occurs
only when a measurement crosses a pre-defined threshold.
A continuous event occurs whenever a
measurement is out of its normal range. The limit test system for the [IH I TOF and LOG programs uses
continuous limits.
For example, suppose a limit test is applied to a level gauge, and the setup file specifies that a message is to
be printed when the level rises above a certain level. If the measurement remains above the critical point
for a large number of measurements, the printout might be rather long and redundant if the FE IMT
action is specified. A limit program could be used to build a transition action.
What followsis the syntax for the limit action program, and two examples.
E.1 SYNTAX
The MOMITOR and LCIG programs call the limit program passing the value of the measurement that
triggered the limit action.
The value passed to the limit program has already been processed by a
conversion program, if any. The syntax for a limit program header is:
SLE subprogram-name' measurement
The measurement is passed to the program as a real number which should not be altered by the limit
program.
E.2 CONTINUOUS EVENTS
Continuous events occur each time a measurement is found to be out of its specified bounds by the
MOM I TOR or LIS program.
Program example:
1a SUE ALARMOCED
8 IF Re=28 THEH SA
28 CLOSE 18CLOSE
11
48 GOTO 126
28 IF R:43.ee THEM 28
el OFEM 168 © OFEM 11
7B FREIMT "Heaters off at
"iTIMEF
SE GOTO 126
28 OFEH 21 ® FOR I=1 TO 5
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