Campbell Scientific CR10 CR10 Measurement and Control - Page 52

SECTION

3.

INSTRUCTION SET

BASICS

90, Step Loop

lndex,

allows

the

increment step

to

be

changed.

See

Instructions 87 and

90,

Section

12,for

more details.

To

index an input location (4

digit

integer) or set

port

command

(2

digit

integer) parameter, C

or

"-" is pressed

after

keying the

value

but before

entering

the parameter. Two

minus

signs

(-)

will

be

displayed to

the

right

of

the

parameter.

3.5

VOLTAGE

RANGE

AND

OVERRANGE

DETECTION

The

voltage

RANGE

code

parameter

on

InpuVOutput lnstructions is used to specify

the

full

scale

range of

the

measurement and

the

integration period for

the

measurement (Table

3.s-1).

The

full scale

range selected should

be

the

smallest that will accommodate the full scale

output

of

the

sensor

being

measured.

Using

the smallest possible range

will

result

in

the

best resolution for

the

measurement.

Four ditferent integration sequences are

possible. The

relative immunity of

the

integration sequences

to

random noise

is:

60

Hz

rei.

=

50 Hz

rei. >

2.72ms

integ.

> 2721ts

integ.

The

60

Hz rejection integration rejects

noise

from 60

Hz

AC

line

power.

The

50

Hz

rejection

is

for countries whose electric utilities

operate at

50

Hz (Section

13.1).

When

a

voltage

input exceeds

the

range

programmed, the value

which

is stored

is

set to

the

maximum negative number and displayed

as -99999 in high resolution or

-6999

in low

resolution.

An

input voltage greater than +5 volts on one of

the analog inputs

will

result

in

errors and

possible overranging on the other analog

in

Voltages greater

than

16

volts

may

damage

the

CR10.

3.6

OUTPUT

PROCESSING

Most

Output

Processing Instructions require

both

an lntermediate

Data Processing

and

a

FinalData

Processing

operation.

For

example, when the

Average

Instruction,

71,

is

initiated,

the

i

ntermediate

processi

n

g

operation

increments a sample count and adds

each

new

lnput Storage value to

a

cumulative total

residing

in

lntermediate

Storage.

When the

Output Flag

is

set, the

final

processing

operation divides the cumulative

total

by the

number of samples to find the

average.

The

average

is

then stored

in

finalstorage

and the

cumulative

totaland

number of samples are set

to zero in Intermediate Storage.

Final Storage

Area

1

(Sections

1.5,

2.1)

is

the

default destination of data output by Output

Processing

Instructions.

Instruction

80

may

be

used to direct output to

either

Final Storage

Area2

or

to

lnput Storage.

Output

Processing

lnstructions

requiring

intermediate processing sample

the

specified

input location(s) each time

the

Output

lnstruction is executed, NOT each time

the

location value is updated by

an l/O

Instruction.

For

example:

Suppose

a

temperature

measurement is initiated

by

Table

1

which

has

an

execution

intervalof

1

second.

FullScale

Range

Resolution*

TABLE

3.5-1.

lnput Voltage

Ranges and Codes

Range Code

Slow

Fast

2.72ms

250

us

60

Hz

Integ.

Integ.

Reject.

*

Differential measurement. resolution

for

50 Hz

Reject.

pV

pV

pV

pV

pV

1112131

2122232

3132333

4142434

5152535

t2.5

mV

t7.5

mV

x25

mV

1250

mV

t2500

mV

0.33

1.

3.33

33.3

333.

NOTE:

Voltages in excess of

5.5

volts

applied to

a

control port can cause

the

CR10

to

malfunction.

3-2

measurement

is

twice

value

shown.

Campbell Scientific CR10 CR10 Measurement and Control - Page 52

Integ.

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