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SECTION
12.
PROGRAM CONTROL INSTRUCTIONS
The user
pressure
t
hour averages
of
the vapor
lated from the
wet- and dry-bulb
of 5
psychrometers. One
pressure
measurement is also
available
for pse
in
the
vapor pressure
calculation.
1.
The inpuf locations are assigned as follows:
a)
presspre
-
location
10
b)
dry-bqrlb
temperatures
-
location
1
1-15
c)
wet-blrlb
temperatures
-
location 16-20
d)
calcufbted
vapor pressure
-
location 16-20
(vapof pressure
is
written over the wet-
bulb temperatures.)
2.
The program flow
is
as follows:
a)
Enter
the Loop Instruction 87 with
delay=0 and iteration count=5.
b)
Calc(late the vapor pressure with
Instrultion 57 using a normal location
entry
of
10
for
atmospheric pressure
and lhdexed locations of
1
1,
16
and
16
for thF dry-bulb, wet-bulb and calculated
vaporl
pressure, respectively.
c)
End lpop
with Instruction
95.
d)
Use
tfre
lf
Time Instruction 92 to set the
Outpqrt
Flag
every hour.
e)
Use tfre
Average Instruction 71 with
5
repetitions starting
at Input Location
16
to
avfrage
the
vapor pressure over the
nour.]
The actual kpyboard entries for the examples
are shown bblow with the first example
Instruction
lQcation
equalto 10. The
Input
Instructions
fo
make
the pressure and
temperature measurements are assumed.
Loop Example: Block
Data
Transform
Beginning
of Loop
Delay
Loop Count
Wet/Dry Bulb Temp to VP
Pressure Loc
Dry Bulb
Temp Loc DRY
BLB#1
Wet Bulb Temp Loc VP
#1
Loc [:VP
#1
1
End
lf
time
is
minutes into a
minute interval
Set high Flag
O
(output)
Average
Reps
Loc VP
#1
TABLE
12.3.
10:
P87
01:
0
02:
5
11:
P57
01:
10
Q2:
11--
03:
16--
04:
16--
12:
P95
13:
P92
01:
0
02:
60
03:
10
14:
P71
01:
5
O2:
16
The Loop with
a
delay may be used so that only
those instructions within the Loop are executed
while certain
conditions are
met.
As
a
simple
example, suppose it is desired
to execute one
set of instructions
from midnight
until6
AM,
another set between
6
AM and
4 PM, and
a
third
set between
4 PM and
midnight.
Between
6
AM
and
4 PM, samples are desired every
10
seconds;
the rest
of
the
time one minute
between
samples is
sufficient.
The execution
interval
is
set
to 10 seconds; when
a
one minute
sample rate
is
desired,
a
delay of
6
(6
x 10s
=
60s) is used
in
the loop.
TABLE 12-4. Example: Loop with Delay
Execution Interval =
10
seconds
01:
01:
01:
02:
11:
01:
1
10
P87
6
0
P86
1
Table 1 Programs
Sec.
Execution Interval
Beginning of Loop
Delay
Loop Count
Do
CallSubroutine
1
12-3
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