Campbell 21X Manuale dell'Operatore Scaricare il pdf (Pagina 131)

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

1 2 ... 126 127 128 129 130 131 132 133 134 135 136 ... 190 191

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