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Campbell Scientific CR7 Measurement and Control System User Manual

Page 142

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SECTION 13. CR7 MEASUREMENTS

13-18

TABLE 13.5-2. Calculating Resistance Values from Bridge Measurement

Instr.

Result

Instr.

Multiplier and Offset

4

X

V R

R

R

x

s

s

f

=

+

(

/ (

))

R

R

X V

X V

s

f

x

x

=

/

/

1

4.

59.

Mult. = 1/V

x

; ofs. = 0

Mult. = R

f

R

X V

X V

R

f

x

x

s

=

1

1

((

/

) / (

/

)) /

4.

59.
42.

Mult. = 1/V

x

; ofs. = 0

Mult. = 1/R

s

5

X

R

R

R

s

s

f

=

+

/ (

)

R

R

X

X

s

f

=

1

5.

59.

Mult. = 1; ofs. = 0
Mult. = R

f

R

X

X

R

f

s

=

1

1

(

/ (

)) /

5.

59.
42.

Mult. = 1; ofs. = 0
Mult. = 1/R

s

; ofs. = 0

6 or 9*

X

R

R

R

R

R

R

=

+

+

1000

3

3

4

2

1

2

[

/ (

)

/ (

)]

*used for full bridge

R

X

X

R

1

1

1

2

1

1

=

(

/ (

)) /

6 or 9.

59.
42.

Mult. = -0.001; ofs. = R

3

/(R

3

+R

4

)

Mult. = 1/R

2

where X

1

3

3

4

1000

= −

+

+

X

R

R

R

/

/ (

)

R

R X

X

2

1

2

2

1

=

(

/ (

))

6 or 9.

59.

Mult. = -0.001; ofs. = R

3

/(R

3

+R

4

)

Mult. = R

1

where X

2

1

= X

R

R

X

X

3

4

3

3

1

=

(

/ (

))

6 or 9.

59.

Mult. = 0.001; ofs. = R

2

/(R

1

+R

2

)

Mult. = R

4

where X

3

2

1

2

1000

=

+

+

X

R

R

R

/

/ (

)

R

X

X

R

4

4

4

3

1

1

=

(

/ (

)) /

6 or 9.

59.
42.

Mult. = 0.001; ofs. = R

2

/(R

1

+R

2

)

Mult. = 1/R

3

where X

4

3

= X

7&9*

X

R

R

s

f

=

/

*used as half bridge

R

R X

s

f

=

7 or 9.

Mult. = Rf; ofs. = 0

R

R

X

f

s

=

/

7 or 9

42.

Mult. = 1/R

s

; ofs. = 0