Campbell 21X Instrukcja Operatora Pobierz pdf (Strona 42)

SECTION

3. INSTRUCTION

SET BASICS

set

high. This flag is

used

to

restrict

sampling

for

averages, totals,

maxima, minima,

etc., to

times

when certain

criteria

are

met.

The flag is

automatically

set low at

the beginning

of the

program

table.

As

an example,

suppose it is desired

to

obtain

a

wind

speed

rose

incorporating

only wind

speeds

greater

than

or equal

to

4.5

m/s. The

wind

speed rose is

computed using the

Histogram

Instruction

75,

and wind

speed

is

stored in Input

location 14, in

m/s. Instruction 89 is

placed

just

before lnstruction 75

and is used to

set Flag 9

high

if the wind

speed

is

less than 4.5

m/s:

TABLE

3.7-2.

Example of

the

Use

of

Flag

9

Param.

No.

Entry Description

89 lf wind

speed

< 4.5

m/s

14 Wind speed

location

4

Comparison:<

4.5

Minimum wind

speed

for histogram

19 Set Flag t high

75

Histogram

86 Do

29

Set Flag 9 Low

3.8 PROGRAM

CONTROL LOGICAL

CONSTRUCTIONS

Most of

the Program Control lnstructions

have

command

code

parameter

which is

used to

specify the

action to be

taken

if

the condition

tested in the instruction

is true. Table 3.8-1

these codes.

TABLE

3.8-1. Command Codes

Inst.

Loc.

X

0

1-9,77-99

10-1

I

20-29

30

31

32

41-46

51-56

61-66

71-76

Go

to end

of

program

table

Call Subroutine

1-9,

77-99

Set

Flag

0-9

high

Set

Flag

0-9

low

Then Do

Exit

loop

if true

Exit

loop

if false

Setport1-6high

Setportl-6low

Toggleportl

-6

-

Pulse

port

1

-

6 100 ms

NOTE: Flag

9

is

automatically reset

the

same

as Flag 0. lf

the

intermediate

processing

disable

flag

is

already set high and

the

test

condition

of a

subsequent Program

Control

Instruction

acting on Flag

9

fails, the flag

is set low. This feature

eliminates having

to enter another

instruction

to specifically reset Flag 9

before

proceeding

to another

group

of test conditions.

3.7,3 USER

FLAGS

Flags

1-8 are not

dedicated to a specific

purpose

and are

available to

the

user for

general programming

needs. The

user flags

can be

rnanually

toggled from the keyboard

in

the

*6

Mode

(Section

1.3)

or

from

a computer

using TERM's monitor

feature. By inserting

flag

tests

(lnstruction

91) at appropriate

points

in

the

program,

the user can manually

set flags to

direct

program

execution.

3.8.1 IF

THEN/ELSE

COMPARISONS

When Command 30, THEN

DO,

is used

with

one

of

the lF Instructions,

88-92,

the instruction

is

followed immediately by instructions to

execute if the

comparison

is true. The Else

lnstruction,

94,

is optional

and

is followed by

the

instructions to

execute

if the comparison is

false.

The

End Instruction, 95, marks the end

of the

branching started

by

the lF

Instruction.

Subsequent

instructions

are

executed

regardless

of the

outcome

of

the comparison

(Figure

3.8-1).

rF

(8J

0R

88-92

W|TH

COMMAND

I

TRUE

ErsE

(e4)

(es)

FIGURE

3.8-1.

lf Then/Else Execution

Sequence

X+1

X+2

P

1

2

3

4

P

P

1

FALSE

i

IND

I

3-4

1 2 ... 37 38 39 40 41 42 43 44 45 46 47 ... 190 191

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