Campbell Scientific CR10 CR10 Measurement and Control - Page 119

SECTION

8.

PROCESSING

AND PROGRAM CONTROL EXAMPLES

8.8

USE OF

2 FINAL STORAGE AREAS

.

SAVING DATA

PRIOR

TO

EVENT

One

of

the

uses

of

2

Final Storage

Areas

is

to

save

a

fixed

amount of

data

before and

after

some event.

ln this example,,a load cell is measured every

second.

lt

is assumed

that

at

some

random

intervalthe

load

willexceed

25

pounds

for

less

than

10

seconds.

Exceeding

25

pounds

is

the

event

to

be

captured.

The data from

the

10

seconds before the event

and

10

seconds

after

the

event

is

to

be

saved

(21

seconds

including

the scan in which

the

load first exceeds 25

pounds).

Every second the load cell is measured; hours-

minutes, seconds, and

the

load are output

to

Final Storage Area

2

(4

values with the Array

lD).

84

locations

are

allocated

to

Final Storage

Area2.

Thus, Area

2

holds

21 seconds

(4

values/second x 21 seconds

=

84

locations).

When

25 pounds

is

exceeded,

10

is loaded into

an

input location and

flag

1

is set

high.

The

input location is used as a down

counter.

The

flag

indicates an

event

has occurred and

prevents

the

input location

from being

reloaded

until

11

seconds

have passed.

The down

counter

is

decremented by

1

each

time the

table

is

executed.

When

it

equals

0

all

the

data

in

Final

Storage Area2

is

transferred

to

Final Storage

Area

1

(using lnstruction 96) and

Flag

1 is

set

low.

The

down

counter

is set

to

10

instead

of

11

because it is decremented after checking

to

see

if it

is 0.

Input Location Labels:

1:FORCE LBS

2:DOWN CNT

*

1

TablelPrograms

01:

1

Sec. Execution lnterval

PG

FullBridge

1

Rep

22

7.5

mV

60

Hz rejection Range

1

lN Chan

1

Excite

all

reps

w/EXchan

1

25OO

mV Excitation

1

Loc

[:FORCE

LBSI

33.333

Mult

0

Offset

03:

P80

01:

2

O2:

10

04:

P77

01:

11

05:

P70

01:

1

02:

1

02:

P86

01:

10

13:

P91

01:

11

02:

30

14:

P96

01:

81

15:

P86

01:

21

16:

P95

17:

P94

18:

P34

01:

2

Q2:

-1

03:

2

19:

P95

Do

Set high Flag

0

(output)

Set Active Storage Area

FinalStorage Area2

Anay

lD

or

location

RealTime

Hour-Minute,Seconds

Sample

Reps

Loc

FORCE LBS

lf X<=>F

X

Loc FORCE LBS

>=

F

Then

Do

lf

Flag/Port

Do

if

flag

1

is low

Then

Do

Do

Set high

Flag

1

Z=F

F

Exponent

of

10

Z

Loc

[:DOWN

CNT

]

End

End

lf X<=>F

X Loc DOWN

CNT

F

Then

Do

lf

Flag/Port

Do

if

flag

1

is high

Then

Do

SerialOutput

All

data

to other

FS

Area

Do

Set low

Flag

1

End

Else

Z=X+F

X Loc

DOWN CNT

F

Z

Loc

[:DOWN

CNT

]

End

End

Table

1

06:

P89

01:

1

02:

3

03:

25

04;

30

07:

P91

01:

21

02:

30

08:

P86

01:

11

09:

P30

01:

10

02:

0

03:

2

10:

P95

11:

P95

12:

P89

01:

2

02:

1

03:

0

04:

30

01:

01:

02:

03:

04:

05:

06:

Q7:

08:

8-9

Campbell Scientific CR10 CR10 Measurement and Control - Page 119

Final Storage Areas, Saving Data

Page 119 highlights