Campbell CR23X, Руководство оператора

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SECTION 12. PROGRAM CONTROL INSTRUCTIONS
12-2
NOTE: Do not set the output flag in an
interrupt subroutine unless it is the only
place the output flag is set and data are
output.
NOTE: If Control Ports 5, 6, 7, or 8 are
used for pulse measurements or interrupt
subroutines, the CR23X will go into a 10
mA power drain state.
PARAM. DATA
NUMBER TYPE DESCRIPTION
01: 2 Subroutine number
(1-9, 79-99)
*** 86 DO ***
FUNCTION
This Instruction unconditionally executes the
specified command.
PARAM. DATA
NUMBER TYPE DESCRIPTION
01: 2 Command (Table 12-2)
*** 87 LOOP ***
FUNCTION
Instructions included between the Loop
Instruction and the End Instruction (95) are
repeated the number of times specified by the
iteration count (Parameter 2), or until an Exit
Loop command (31,32) is executed by a
Program Control Instruction within the Loop. If
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.
Its units are multiples of 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 a loop with delay
is executed, the next execution starts at the
loop, skipping over any previous and following
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 CR23X 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 if Table 1 is to be executed.
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