Campbell Scientific CR10 CR10 Measurement and Control - Page 19

OVl.2

CONNECTING

POWER TO

THE

CRlO

The

CR10

can

be powered

bY

anY

12VDC

source.

First connect

the positive

lead from

the

power supply

to

one

of

the

12V

terminals

and

then connect

the

negative lead

to

one

of

the

power

ground

(G)

terminals.

The

Wiring

Panel

power connection is reverse polarity protected.

See

Section

14

for details on power supply

connections.

CAUTION:

The

metal surfaces of

the

CR10

Wiring

Panel, and

CR1OKD

Keyboard

Display are

at

the

same

potentialas

power

ground.

To avoid

shorting

12

volts

to

ground, connect

the

12

volt

lead first, then

connect

the

ground lead.

OV2.

MEMORY

AND

PROGRAMMING

CONCEPTS

The

CR10 must be programmed

before

it

will

make

any measurements.

A program consists

of a group

of

instructions

entered

into

a

program

table.

The

program

table

is given an

execution interval

which determines how

frequently that

table

is

executed.

When

the

table

is

executed,

the

instructions are executed

in

sequence

from

beginning to

end.

After

executing the table,

the

cR10

waits

the

remainder

of

the execution

interval and then

executes

the

table again starting

at

the

beginning.

The intervalat

which the

table

is

executed

generally determines

the

interval

at

which the

sensors

are measured. The interualat

which

data are

stored

is

separate

from

how often

the

table

is executed,

and

may range

from

samples

every

execution

interval

to

processed

summaries output hourly, daily, or

on

longer

or

irregular intervals.

Figure

OV2.1-1

represents

the

measurement,

processing, and data storage seguence, and

the

types

of instructions used

to

accomplish

these tasks.

"

cR10

ovERvlEw

OV2.1

INTERNAL

MEMORY

The

CR10 has

64K

bytes

of

Random Access

Memory (RAM),

divided

into

five

areas.

The

use of

the lnput,

Intermediate,

and

Final

Storage

in

the

measurement and data

processing sequence is shown

in

Figure OV2.1-

1.

While the

total

size

of

these

three

areas

remains

constant,

memory may

be

reallocated

between the areas

to

accommodate different

measurement

and

processing needs (*A Mode,

Section

1.5).

The size

of

the 2 additional

memory areas, system and program, are fixed.

The five areas

of

RAM

are:

1.

Input Storage

-

lnput

Storage

holds

the

results

of

measurements or calculations.

The'6

Mode is used to

view

lnput Storage

locations for checking

current sensor

readings or calculated

values.

lnput

Storage defaults to

28 locations.

Additional

locations

can

be

assigned

using

the'A

Mode (Section

1.5)"

2.

Intermediate Storage

-

Certain

Processing

Instructions

and

most of the Output

Processing Instructions maintain

-'

intermediate

results

in

Intermediate

Storage.

Intermediate

storage

is

automatically accessed by

the

instructions

and

cannot

be

accessed

by

the

user.

The

default

allocation

is 64

locations. The

number

of

locations can be

changed

using

the

*A

Mode.

3.

Final-Storage

-

Finalprocessed

values are

stored

here for transfer

to

printer, solid state

Storage Module or

for

retrieval via

telecommunication

links.

Values

are stored

in FinalStorage

only by the Output

Processing Instructions and only when the

Output

Flag is set

in

the

users program.

Approximately 29,900 locations are

allocated

to

Final Storage

on

power

up.

This

number is reduced

if lnput

or

Intermediate Storage is increased.

4.

System

Memory -

used for overhead tasks

such as

compiling

programs, transferring

data

etc.

The

user

cannot

access

this

memory.

5.

Program

Memory

-

available

for

user

programs

entered

in

program

tables

1

and

2, and Subroutine

Table

3.

ov-5

Campbell Scientific CR10 CR10 Measurement and Control - Page 19

MEMORY, PROGRAMMING, CONCEPTS, table., ovERvlEw, The'6

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