Campbell Scientific CR10 CR10 Measurement and Control - Page 128

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SECTION

9.

INPUT/OUTPUT INSTRUCTIONS

PARAM.

BATA

NUMBER

TYPE

DESCRIPTION

Repetitions

Flange

Code (Table 9-1)

Single-ended channel

number

Excitation channel

number

Excitation voltage

(millivolts)

Input location number

for

first

measurement

Multiplier

Offset

Input locations

altered:

1

per measurement

***

6

FULL

BRIDGE WITH

SINGLE

***

DIFFERENTIAL

MEASUREMENT

FUNCTION

This

Instruction is used to apply an excitation

voltage to

a

full

bridge and make a ditferential

voltage

measurement

of

the

bridge

output.

The

measurement is made with

the

polarity

of

the

excitation voltage both positive and negative

(Figure

13.5-1). The

result is 1000 times

the

ratio

of

the

measurement to

the

excitation

voltage.

A

1

belore

the excitation channel

number (1X) causes the

channelto

be

incremented with

each

repetition.

PARAM.

DATA

NUMBER

TYPE

DESCRIPTION

Repetitions

Range

code

(Table 9-1)

Ditferential channel

number for

first

measurement

Excitation channel

number

Excitation voltage

(millivolts)


for

first

measurement

Multiplier

Offset

Input locations

altered:

1

per

measurement

.**

7

THREE

WIRE HALF

BRIDGE

***

FUNCTION

This

Instruction is used

to

determine

the

ratio of

the

sensor

resistance

to a

known resistance

using

a

second voltage sensing wire from the

sensor to compensate

for

lead

wire

resistance.

The

measurement

sequence

is

to apply

an

excitation

voltage,

make two voltage

measurements on two adjacent single-ended

channels, the first on

the

reference resistor and

the second on the

voltage

sensing wire from

sensor (Figure 13.5-1),

then

reverse

the

excitation voltage

and

repeat the

measurements.

The

two

measurements are

used to calculate

the

resulting value,

which

is

the

ratio of the voltage across the sensor to the

voltage across

the

reference

resistor.

A

1

before the excitation

channel

number

(1X)

causes the

channelto

be incremented with

each

repetition.

PARAM.

DATA

NUMBER

TYPE

DESCRIPTION

Repetitions

Range code

for

both

measurements (Table

e-1)

Single-ended channel

number for

first

measurement

2

Excitation channel

4

Excitation voltage

(millivolts)


for

first

measurement

FP

Multiplier

FP

Otfset

Input locations

altered:

1

per measurement

***

8

DIFFERENTIAL VOLTAGE

WITH

*'*

EXCITATION

AND DELAY

FUNCTION

This

measurement consists of applying a single

excitation voltage, delaying a specified time,

and making

a

differential

voltage

measurement.

The

result

stored

is

the

voltage

measured.

"Delay" (Parameter

5)

refers

to

increasing the

signal settling

time

by increasing the time

between

the

start

ol

excitation and the start

of

signal integration (Section

13.2).

lf a delay

of 0

2

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05:

oGi

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Campbell Scientific CR10 CR10 Measurement and Control - Page 128

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