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7.3 INTERNAL

DATA

STORAGE

7.3.1 FINAL

STORAGE AREAS

AND OUTPUT

ARRAYS

Final Storage

the

memory

where final

processed

data

are stored.

Final Storage data

are transferred

your

computer

or external

stbrage

peripheral.

The

size

of Final Storage is

expressed in terms

memory

locations

or bytes.

A low resolution data

point (4

decimalcharacters)

occupies one

memory

location

bytes), whereas

a high

resolution

data

point (5

decimal

characters)

requires

two memory locations

bytes). Figure

7.2-l

shows the default allocation

of memory

locations

to Program, lnput,

lntermediate, and

Final

Storage. The

Mode

is used to reallocate

memory

or erase

Final

Storage

(Section

7.5.1).

The default

size of Final Storage

with standard

memory

is 32,768low resolution

memory

locations.

The

CR500

stores data

strings of

data

points

called

OUTPUT

ARRAYS.

The first

date

point

in the

output array is a 3 digit

OUTPUT

ARRAY

tD.

7.4 DATA

OUTPUT

FORMAT

AND

RANGE

LIMITS

Data

are stored internally

in Campbell

Scientific's

Binary FinalStorage

Format.

Data

may be

sent to

Final

Storage in either LOW

RESOLUTION

or HIGH

RESOLUTION

format.

7.4.1 RESOLUTION

AND RANGE

LIMITS

[-ow resolution

data is a 2

byte format with

significant

digits and a maximum

magnitude of

+6999.

High resolution data

is a 4 byte format

with 5

significant

digits

and a maximum

possible

output value

+99999

(see

Table 7.4-1 below).

TABLE

7.4-1. Resolution

Range Limits of

CR500

Data

Minimum

Maximum

Maqnitude

Low

0.000

+0.001

+6999.

High

0.0000

+.00001 +99999.

The resolution

of the low

resolution format is

reduced

3 significant digits

when

the

first

(left

most)

digit is 7 or

greater.

Thus, it may be

necessary

to use

high resolution

output or an

maintain

the desired resolution

of a

measu

For example, if water level is

to be measured

output to

the

nearest

0.01 ft.,

the

level must be

than 70 ft.

for low resolution output

display

0.01 ft.

increment.

lf the water

levelwas

range from

50 to 80 ft. the

data could either

.output

high resolution or could

be offset by

(transforming

the

range to 30

to 50 ft.).

7.4.2 INPUT

AND INTERMEDIATE STOR

DATA FORMAT

While output

data have the

limits

described

above,

the

computations

performed

in the

CR500

are

done in floating

point

arithmetic. ln

Input and

Intermediate

Storage,

the numbers

ijie

stored

and

processed

a binary

format

with

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 19-19, respectively. The

size of

the

number

determines the

resolution

of the

arithmetic. A

rough approximation

of the

resolution is that it is better

than

1 in the

seventh digit. For example, the resolution of

97,386,924 is better than

10.

The resolution

0.00867319e4 is better than 0.000000001.

precise

calculation

of the resolution of a

number

may be determined by representing

number

as a

mantissa between .5 and 1

multiplied

2 raised to some

integer

power.

resolution is

the

product

of that

power

ol2

and

2'2a. For

example,

representing 478 as .9336

29, the resolution is 29

2-24

2'15

7.4.3 DISPLAYING STORED DATA ON

KEYBOARD/DISPLAY

MODE

(Computer/terminal

users refer

Section 6.10

for

instructions on entering the Remote

Keyboard

State.)

FinalStorage

may be displayed by using the

Mode. Key

*7.

The first

window

displays the

current DSP location. Pressing

A advances

the Output

array

lD of the

oldest

Array in the

Storage Area. To locate a specific Output

Array, enter a location

number

that

positions

Display Pointer

(DPTR)

behind the desired

and

press

the

"A" key.

the location number

entered is in the middle of an Output Array, the

DPTR is

automatically

advanced

to the

first

point

the

next Output Array. Repeated use

Resolution

Zero

the

"A"

key advances through the Output

Array

1 2 ... 35 36 37 38 39 40 41 42 43 44 45 46 47 48

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Campbell CR500 Especificaciones Pagina 40

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