YOKOGAWA WT500, Руководство пользователя

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IM 760201-01E
Features
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App
Index
2.2 Measurement Functions and Periods
Measurement Functions
The physical values (such as rms voltage, average current, power, and phase difference)
that the WT500 measures and displays are called measurement functions. Each
measurement function is displayed using symbols that correspond to its physical value.
For example, “Urms” corresponds to the true rms voltage.
Types of Measurement Functions Used in Normal Measurement
The data of measurement functions (numeric data) is measured or computed from the
sampled data that is described in “Measurement Period” on page 2-9.
1
1 The WT500 samples the instantaneous values of the voltage and current signals at the
specified sample rate. The sampled data is processed as numeric data or data used to
display waveforms on the screen (waveform display data).
The sample rate is the number of data points that are sampled within 1 s. For example, at a
sample rate of 100 kS/s, 100000 data points are sampled every second.
Types of Measurement Functions
• Input Element Measurement Functions
The following 23 measurement functions are available. For details about the
determination of measurement function data, see appendix 1.
U (voltage Urms, Umn, Udc, Urmn, Uac), I (current Irms, Imn, Idc, Irmn, Iac), P (active
power), S (apparent power), Q (reactive power),
λ
(power factor),
f
(phase difference),
fU/fI (also expressed as FreqU/FreqI; measures the frequencies of up to two voltage/
current signals),
2
U+pk/U-pk (maximum/minimum voltage values), I+pk/I-pk (maximum/
minimum current values), and CfU/CfI (crest factor of voltage/current; peak-to-rms
ratio)
2 The voltage and current frequencies of all input elements can be measured on models with
the frequency measurement add-on option.
• Wiring Unit Σ Measurement Functions ( Σ Functions)
The following 15 measurement functions are available. For details about the
determination of measurement function data, see appendix 1.
U
Σ
(voltage average Urms
Σ
, Umn
Σ
, Udc
Σ
, Urmn
Σ
, Uac
Σ
), I
Σ
(current average Irms
Σ
,
Imn Σ , Idc Σ , Irmn Σ , Iac Σ ), P Σ (sum of active powers), S Σ (sum of apparent powers),
Q
Σ
(sum of reactive powers),
λΣ
(power factor average), and
fΣ
(phase difference
average)
•Efficiency ( Σ functions) and User-Defined Functions
There are two efficiency functions, η 1 and η 2. The available user-defined functions
are F1 to F8. For details, see section 2.5.
• Integration Functions
See section 2.6.
• Delta Computation (Optional)
There are four delta functions, Δ F1 to Δ F4. For details, see section 5.17.