Campbell Manufacturing CR10 Manual De Usuario
SECTION 13. CR10 MEASUREMENTS
13-20
Calculating the actual resistance of a sensor
which is one of the legs of a resistive bridge
usually requires the use of one or two Processing
Instructions in addition to the bridge
measurement instruction. Instruction 59 takes a
value, X, in a specified input location and
computes the value MX/(1-X), where M is the
which is one of the legs of a resistive bridge
usually requires the use of one or two Processing
Instructions in addition to the bridge
measurement instruction. Instruction 59 takes a
value, X, in a specified input location and
computes the value MX/(1-X), where M is the
multiplier and stores the result in the original
location. Instruction 42 computes the reciprocal
of a value in an input location. Table 13.5-2 lists
the instructions used to compute the resistance
of any single resistor shown in the diagrams in
Figure 13.5-1, provided the values of the other
resistors in the bridge circuit are known.
location. Instruction 42 computes the reciprocal
of a value in an input location. Table 13.5-2 lists
the instructions used to compute the resistance
of any single resistor shown in the diagrams in
Figure 13.5-1, provided the values of the other
resistors in the bridge circuit are known.
TABLE 13.5-2. Calculating Resistance Values from Bridge Measurement
Instr.
Result
Instr.#
Multiplier;
Offset
4
X = V
x
(R
s
/(R
s
+R
f
))
X/V
x
4
1/V
x
0
R
s
= R
f
________
59
R
f
1-X/V
x
1
4
1/V
x
0
R
f
= ____________________
59
1/R
s
((X/V
x
)/(1-X/V
x
))/R
s
42
5
X = R
s
/(R
s
+R
f
)
X
5
1
0
R
s
= R
f
_____
59
R
f
1-X
1
5
1
0
R
f
= _____________
59
1/R
s
0
(X/(1-X))/R
s
42
6,8,9* X = 1000 [R
3
/(R
3
+R
4
)-R
2
/(R
1
+R
2
)]
*used for full bridge
6 or 9
-0.001;
1
8
1/V
x
R
1
= _______________
6,8, or 9
R
3
/(R
3
+R
4
)
(X
1
/(1-X
1
))/R
2
59
1/R
2
42
where X
1
= -X/1000 + R
3
/(R
3
+R
4
)
R
2
= R
1
(X
2
/(1-X
2
))
6 or 9
-0.001
R
3
/(R
3
+R
4
)
where X
2
= X
1
59
R
1
R
3
= R
4
(X
3
/(1-X
3
))
6 or 9
0.001
R
2
/(R
1
+R
2
)
where X
3
= X/1000 + R
2
/(R
1
+R
2
)
59
R
4
1
6 or 9
0.001
R
2
/(R
1
+R
2
)
R
4
= _______________
(X
4
/(1-X
4
))/R
3
59
1/R
3
42
where X
4
= X
3
7&9* X = R
s
/R
f
* used as half bridge
R
s
= R
f
X
7 or 9
R
f
0