Minebea DSA-631, Инструкция по эксплуатации

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33
(2) Measurement with various types of transducers
This calibration voltage value is linked with the bridge supply voltage, and the amount of
calibration can always be applied with any panel-indicated value (1
x
10
-6
strain
~
9 999
x
10
-6
strain).
Example )
If a load cell with a rated capacity and a rated output of 1 ton and 1 mV/V is used, to convert the
rated output of 1 mV/V into an amount of strain, the rated output is given by :
1 mV/V
x
2 V = 2 mV
Where the load cell is used with the bridge voltage (E) = 2 V
If the measurement is based on the quarter bridge configuration with a gage factor (K) of 2.00, the
relationship between the amount of strain (
ε
) to be applied to the bridge and the output voltage (e) is
given by;
e = 1/4
x
K
x
E
x ε
= 1/4
x
2
x
2
x ε
=
ε
That is, 1
x
10
-6
strain corresponds to 1
μ
V and 1 000
x
10
-6
strain to 1 mV. The rated output of 2 mV
corresponds to 2 000
x
10
-6
strain. As a result, the relationship between calibration values and the
physical amount is as follows irrespective of the bridge supply voltage.
Calibration Strain Calibration Physical Amount
2 000
x
10
-6
strain 1 ton
x
1 = 1 ton
1 000
x
10
-6
strain 1 ton
x
1/2 = 500 kg
500
x
10
-6
strain 1 ton
x
1/4 = 250 kg
200
x
10
-6
strain 1 totn
x
1/10 = 100 kg
Table 4-5
The formula is as follows;
Calibration value of physical amount =
x
Rated capacity
The physical amount can be calculated as follows;
Calibration value of physical amount ; 250 kg (500
x
10
-6
strain)
Deflectin of CAL waveform : 10 mm
Deflection atpoint B : 22 mm
The physical amount can be calculated as follows ;
Load at point B =
x
250 kg = 550 kg
4-4-1. Correction of Calibration (CAL) value
(1) Where gage factors are not 2.00
In this amplifier unit, its gage factor is set to 2.00. If strain gage with a gage factor other than
2.00are to be used, the following formula must be used.
True CAL value =
x
CAL value of unit
Calibration value for 10 -6 strain of the amplifier
Rated output value (10
-6
strain)
22
10
2.00
Kc (Gage factor of strain gage)