Yokogawa Standalone MW100 - Manual (Page 61)

1-47
IM MW100-01E
Explanation of Functions
1
2
3
4
5
App
Index
Scaling Settings of the Strain Gauge Type Sensor
This is an explanation of scaling settings used to measure physical quantities such as
load and length using a strain gauge type sensor.
The basic relational equation is as follows.
1 mV/V = 2000 µSTR (equation 1)
The following gives two examples, one when the rated input and output are known, and
one when the calibration coefficient is known. (Hereinafter, µ-strain will be expressed as
µSTR).
When the Rated Input and Output Are Known
The following specific example provides an explanation.
• Rated input 200N
(set to Y)
• Rated output 0.985 mV/V (set to K)
In this case, if a 200 N load is introduced, an output of 0.985 mV/V results.
From the relationship in equation 1, if 200 N is applied, it means that
an output of: 0.985 mV/V = 0.985 × 2000 = 1970 µSTR is obtained.
In other words, for each 1N, 1970 µSTR/200N = 9.85 µSTR/N of output results.
Therefore, the scaling settings are entered as follows.
When Measuring at 50 to 150 N
Scale minimum: 50
(set to Smin)
Scale maximum: 150 (units: N) (set to Smax)
therefore,
Span minimum: 50 × 9.85 µSTR/N = 492.5 µSTR
Span maximum: 150 × 9.85 = 1477.5 µSTR
would be appropriate settings.
Hence, the measurement range is 2000 µSTR.
Generally, the range is as follows.
Using the symbols explained up to now, after setting the minimum and maximum scale,
we can describe the minimum and maximum values of span as:
Min. value of span = [(K(mV/V) × 2000) / Y(unit)] × Smin (µSTR)
Max. value of span = [(K(mV/V) × 2000) / Y(unit)] × Smax (µSTR)
1.8 Functions of the 4-CH, Medium-Speed Strain Input Module