Campbell CR7, Инструкция по эксплуатации

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SECTION 12. PROGRAM CONTROL INSTRUCTIONS
12-2
0 is entered for the count, the loop is repeated
until an Exit Loop command is executed.
The first parameter, delay, controls how
frequently passes through the loop are made.
The delay unit is the table execution interval:
A delay of 0 means that there is no delay
between passes through the loop. Each
time the table is executed all iterations of
the loop will be completed and execution
will pass on to the following instructions.
If the delay is 5, every fifth time that the
execution interval comes up, one pass
through the loop is made; only those
instructions in the loop will be executed and
other portions of the table are not executed
in the interim. When the loop is executed,
execution starts at the loop, skipping over
any previous instructions in the table.
When a fixed number of iterations are
executed, the time spent in the loop is equal to
the product of the execution interval, delay, and
the number of iterations. For example, a loop
with a delay of 1 and a count of 5 will take 5
seconds if the execution interval is 1 second.
When the loop is first entered, one pass through
the loop is made, then the CR7 delays until the
next execution interval and makes the second
pass through the loop. After making the fifth
pass through the loop, there is the fifth delay,
after which execution passes to the instruction
following the END instruction which goes with
the loop.
While in a loop with delay, the table will not be
initiated at each execution interval. (However,
the overrun decimals will not be displayed.)
Some consequences of this are: The Output
Flag will not be automatically cleared between
passes through the loop. Because Table 2
cannot interrupt Table 1, Table 2 will not be
executed while Table 1 is in a loop with delay.
Table 1 will not interrupt Table 2 in the middle of
an output array. Thus, if the Output Flag is set
in Table 2 prior to entering the loop or within the
loop, the flag must be specifically cleared before
the end of the pass or Table 1 will not be able to
interrupt.
Input locations for Processing Instructions within
a loop can be entered as Indexed locations. An
Indexed location causes the input location to be
incremented by 1 with each pass through the
loop. (The Index counter is added to the
location number in the program table.) Input
locations which are not indexed will remain
constant.
To specify an Indexed location, depress the C
key at some point while keying in the digits for
the input location and before entering the
location with the A key. Two dashes, --, appear
in the two right most characters of the display,
indicating the entry is Indexed.
When the same output processing is required
on values in sequential input locations, it must
be accomplished by using the repetitions
parameter of the Output Instruction, not by
indexing the input location within a loop.
An Output Instruction within a loop is allotted the
same number of Intermediate Storage locations
as it would receive if it were not in the loop. For
example, the Average instruction with a single
repetition is allotted only two Intermediate
locations: one for the number of samples and
one for the running total. Each time through the
loop the sample counter is incremented and the
value in the referenced input location is added
to the total. If the input location is indexed, the
values from all input locations are added to the
same total. If the Average instruction with 1
repetition and location 1 indexed is placed
within a loop of 10 and the Output Flag set high
prior to entering the loop, 10 values will be
output. These will not be the averages for
locations 1-10. The first will be the average of
all the readings in locations 1-10 since the
previous output. Because the Intermediate
locations are zeroed each time an output
occurs, the next nine values will be the current
values (samples at the time of output) of
Locations 2-10.
Loops can be nested. Indexed locations within
nested loops are indexed to the inner most loop
that they are within. The maximum nesting
level in the CR7 is 9 deep. This applies to If
Then/Else comparisons and Loops or any
combination thereof. An If Then/Else
comparison which uses the Else Instruction, 94
counts as being nested 2 deep.