Campbell 21X Manuale dell'Operatore Scaricare il pdf (Pagina 38)

The of the

low resolution

format

is

significant

digits

when

the first

(left

7 or

greater (Table

2.2-2). Thus, it

SECTION 2. INTERNAL

DATA

STORAGE

0.0000305. A

description

of Campbell

Scientific's

floating

point

format may

be

found in

the description of the J and

K

lelecommunications commands

in Appendix

C.

2.3 DISPLAYING

STORED

DATA

ON

KEYBOARD/DISPLAY

.

*7

MODE

The

*7

Mode is used to display

Final

Storage

data. Enter the Mode by

keying

*7.

The display

willshow

"OT:XXXXX",

where XXXXX is the

Final

Storage

location

(DSP)

where

the

next

data will

be stored.

Two options are

available:

1. Press A to advance and display the

output

array lD of the oldest array in

FinalStorage.

2.

Enter a Final Storage

location

number.

When A is

pressed,

the

DPTR

willjump

to the

location

entered

and, if it is not at

the start of

an array, advance

to the

first

start

of array. The display

willshow

the

Array

lD.

Repeated

use of the A key advances through

the output

array,

while

use

of the B

key backs

the DPTR

through memory.

The Final

Storage

location of the data

point

being viewed may

be

displayed by keying #. At

this

point,

another

location may be

entered,

followed

by

A

to

jump

to the start of

the output

array

equal

to or

just

ahead of the

location

entered. Whenever a location number is

displayed

by

keying #, the corresponding data

point

can be displayed by

keying C.

To advance

to

the

start of the next output array, key #A. To

back

up one

output array key

#8.

TABLE

2.3-1.

"7

Mode

Command Summary

Key

Action

Advance

to

next data

point

Back-up to

previous

data

point

Display

location number

of

currently

displayed data

point

value

Display value of current

location

Advance

to start

of next

output array

Back-up to

previous

outout

arrav

reduced

to

most)

digit

may

be

to use

high resolution

output

or an

offset

maintain

the

desired resolution of

a . For example,

if water

level

is

to be red and output to

the

nearest 0.01

foot,

the must be

less than

70

feet for low

resolution

oltput to display

the 0.01 foot

increment.

lf the

water level

is expected

to

range

from

F0

to 80 feet the data could either be

output in hi$h resolution or could

be

otfset by

20

feet.

(transfprming

the range to 30 to 60 feet.).

TABLE Decimal Location in Low

Resolution

Format

Value Decimal Location

X.XXX

XX.XX

XXX.X

XXXX.

6.999

69.99

699.9

6999.

While

outprit data

have

the

limits

described

above, the

$omputations

performed

in

the

21X

are done in

lfloating

point

arithmetic. Values

are

rounded

wfen converting

to Final

Storage

Format.

2.2.2 rNpUT

AND

TNTERMEDTATE STORAGE

DATA

FORMAT

In Input

and

Intermediate Storage, numbers are

stored and

processed

in a binary format with

a

23 bit

binary

mantissa and a

6 bit

binary

exponent.

The

largest and smallest numbers

that can be stored

and

processed

are 9

x 1018

and 1 x 10-'!e,

respectively. The

size of the

number

detbrmines

the resolution

of the

arithmetic.

f,

rough approximation

of the

resolution id

that

it is better than 1 in the seventh

digit. For ei<ample, the

resolution

of 97,386,924

is better

than

10. The

resolution

of

0.0086731q24 is better than

0.000000001.

A

precise

calculation

of the resolution

of

a

number may

be

determined by

representing

the

number

as a

mantissa between

.5

and

1

multiplied

by 2

raised to some integer

power.

The

resolution

is the

product

of that

power

of

2

and 2-24. Fpr example,

representing

478 as

.9336

*

Zs,

Jne

resolution is 2e

*

2'2a

-

2'15

-

0-

7-

70

700

A

B

#

c

#A

#B

2-3

1 2 ... 33 34 35 36 37 38 39 40 41 42 43 ... 190 191

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