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CR10X User Guide
3-4
Table 3-2 Flag Description
Flag 0
–
Output Flag
Flag 1 to 8 –
User Flags
Flag 9
–
Intermediate Processing Disable Flag
Flags are set with Program Control Instructions. The Output Flag (flag 0) and the
intermediate programming disable flag (flag 9) are always set low if the set high
condition fails. The status of flags 1-8 does not change when a conditional test is
false.
3.7.1 The Output Flag
A group of processed data values is placed in Final Storage by Output Processing
Instructions when the Output Flag (flag 0) is set high. This group of data values is
called an Output Array. The Output Flag is set using Program Control Instructions
according to time- or event-dependent intervals specified in your program. The
Output Flag is set low at the beginning of each table.
Output is most often desired at fixed intervals; this is done with Instruction 92, If
Time. Output is usually desired at the start of the interval, so parameter 1, time
into the interval, is 0. The time interval (parameter 2), in minutes, is how often
output will occur, i.e. the Output Interval. The command code (parameter 3) is 10,
causing flag 0 to be set high. The time interval is synchronised to 24-hour time;
output occurs on each integer multiple of the Output Interval starting from
midnight (0 minutes). If the Output Interval is not an even divisor of 1440 minutes
(24 hours), the last output interval of the day is less than the specified time
interval. Output occurs at midnight and resumes synchronised to the new day.
Instruction 92 is followed in the program table by the Output Instructions which
define the Output Array desired.
Each group of Output Processing Instructions creating an Output Array must be
preceded by a Program Control Instruction that sets the Output Flag.
If the Output Flag is already set high and the test condition of a
subsequent Program Control Instruction acting on flag 0 fails, the
flag is set low. This feature eliminates having to enter another
instruction to specifically reset the Output Flag before proceeding to
another group of Output Instructions with a different output
interval.
3.7.2 The Intermediate Processing Disable Flag
The Intermediate Processing Disable Flag (flag 9) suspends intermediate proc-
essing when it is set high. This flag is used to restrict sampling for averages,
totals, maxima, minima, etc. to times when certain criteria are met. The flag is
automatically set low at the beginning of the program table.
As an example, suppose it is desired to obtain a wind speed rose incorporating
only wind speeds greater than or equal to 4.5ms
-1
. The wind speed rose is com-
puted using the Histogram instruction (Instruction 75), and wind speed is stored in
input location 14, in ms
-1
. Instruction 89 is placed just before Instruction 75 and is
used to set flag 9 high if the wind speed is less than 4.5ms
-1
(see Table 3-3).
NOTE