YOKOGAWA WT210, User Manual, Page: 83 / 316

4-15
IM 760401-01E
Setting Measurement Conditions and Measurement Range
4
Selecting the Measurement Range (Current with Scaling Function ON)
ENTER
3.
When equipped with option /EX1
( Display C )
1.
CURRENT
When equipped with option /EX2
( Display C )
2.
ENTER
3.
2.
End of setting
The unit is “V.” The unit is “mV.”
End of setting
The above figure shows the selections when
the crest factor is set 3. The selections when
the crest factor is set to 6 are shown below.
Auto , 10 , 5 , 2.5 , 1 , 0.5 , 0.25 ,
E 5 , E 2.5 , E 1.25
The above figure shows the selections when
the crest factor is set 3. The selections when
the crest factor is set to 6 are shown below.
Auto , 10 , 5 , 2.5 , 1 , 0.5 , 0.25 ,
E 100 , E 50 , E 25
The menu above is for the WT230. The WT210 displays mA range followed by the
external sensor range (mV or V unit).
Explanation
Scaling Function in combination with External Sensor Input
This function is used when measuring the voltage or current by installing an external
sensor and connecting its output to the input element of the WT210/WT230.
Setting Example of Scaling Constant for External Sensor Input
• In case the rated specs of the external sensor are 50 A/50 mV, measurement
range is 50 mV, then
50 A/50 mV
×
50 mV = 50 A: scaling constant is 50.00
• In case the rated specs of the external sensor are 100 A/50 mV, measurement
range is 50 mV, then
100 A/50 mV
×
50 mV = 100 A: scaling constant is 100.00
• In case the rated specs of the external sensor are 50 A/80 mV, measurement
range is 50 mV, then
50 A/80 mV
×
50 mV = 31.25 A: scaling constant is 31.25
However, since the setting range is 50 mV, use a setting within the 0 to 50 mV
range.
This instrument uses this scaling coefficient in calculations like the ones below to
obtain current values for display or output as data.
Current value =
Measurement range value for the external sensor
Output voltage of the external sensor
×
Scaling constant
The current value is used to determine the active power, reactive power, and
apparent power to be displayed or output as data. The scaling function explained
here is completely different from the PT/CT scaling function explained in the
previous section.
4.6 Selecting the Measurement Range and Setting the Scaling Constant when External Sensor is Used (option)