NF ZM2371, Инструкция по эксплуатации

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8.7 Performance Testing
8-7 ZM2371/ZM2372
8.7.5 AC Impedance Measurement Accuracy
Described here is the easy checking method. For the correct test, request NF Corporation to
make test.
Standard:
To make correct test, prepare the standard with approx 1/3 or less in
calibration accuracy against the accuracy of
ZM2371 / ZM2372
.
Unless there is standard, prepare the standard stabilized specimen which
was corrected by the precise measurement instrument. You can conduct the
test depending on the calibration accuracy and stability factor of the
standard provided. For the measurement of low impedance, it may suffer
an influence of contact resistance. Accordingly, use the standard of
4-terminal structure.
The pseudo-capacitance standard with transformer cannot be used for
ZM2371 / ZM2372
. If standard having extremely large capacitance to earth
(to shield) is used, LCR meter gets unstable, disabling the measurement.
Compared with the normal parts, the standard capacitor with large
capacitance to shield may cause a considerable error at high frequency and
high impedance range.
Reference: For the range of approx 10Ω to 1MΩ having a good frequency response,
even the resistor for which calibration value of impedance is not provided
at each frequency can make a simple test using the calculated values
stated below. Especially, for the shunt resistor with a good frequency
response, the calculated values can be used even for 1Ω or 100mΩ in the
same manner.
・
Calibration value Rdc of DC resistance
・
Equivalent series inductance Ls[H] at 1MHz or
Ｅ
quivalent parallel
capacitance Cp[F]
Complex impedance Z
．
= Rdc +
j
ω Ls or Z
．
= Rdc
-
j
1/(ω Cp)
|Z
．
| =
√
( Rdc
2
+ (ω Ls)
2
) or |Z
．
| =
√
( Rdc
2
+ 1/(ω Cp)
2
)
θ ( =
∠
Z
．
) = tan
-1
(ω Ls / Rdc) or θ =
-
tan
-1
(ω Cp Rdc)
where angular frequency ω = 2
π
f, f is frequency [Hz]
Connection: Standard →
ZM2371 / ZM2372
measurement terminal
Setting: After initializing the setting, setting as shown below.
Measurement frequency = 120Hz, 1kHz, 10kHz, 100kHz
Measurement signal level = 1V (initial value)
Measurement speed = SLOW, Averaging count = 1 (initial value)
Cable length correction = 0m (initial value) or Set depending on the cable
used.
Measurement range = Fix it to the specified range.
Auto selection may not allow the specified measurement range. Accordingly,
be sure to fix it to the specified measurement range.
Measurement: First, measures the open correction and short correction.
Thereafter, measure the standard according to the contents in table shown
below.
Evaluation: If the measurement values are within the range stated below, it is
approximately correct.
Calibration value of standard
±
(Calibration accuracy of st
accuracy of
ZM2371 / ZM2372
)