Table of Contents
Advertisement
10.1 Waveform Computation Function
10-2
• Equation Examples
• Instantaneous Power Waveform
To multiply the voltage waveform by the current waveform of input element 1 and
display the instantaneous power waveform, set the equation to P1.
• Voltage and Current Waveforms of a Three-Phase, Three-Wire System
To display the voltage between the phases R and S and the current of phase T of
a three-phase, three-wire system when there are only two input elements, set the
equations as follows:
Math1: U1-U2
Voltage between phases R and S = ( voltage between phases R and T) - (voltage
Math2: -(I1+I2)
Current of phase T = -(current of phase R + current of phase S)
• Current Waveform of the Neutral Line of a Three-Phase, Four-Wire System
To display the current waveform of the neutral line of a three-phase, four-wire
system when there are only three input elements, set the equation as follows:
Math1: -(I1+I2+I3)
Current of the neutral line = -( current of phase R + current of phase S + current
• Instantaneous Waveform of Motor Output (Mechanical Power)
To multiply the motor's torque signal by the speed signal and display the
instantaneous waveform of the motor output, set the equation to Pmi.
• Eliminating the Noise from the Computed Waveform
Use averaging (AVG) to eliminate high frequency components from the computed
waveform. The noise elimination effect is higher as the attenuation constant is
increased. However, the response delay also increases as compared to when
averaging is not used.
• Limitations on the Function and Measurement Function
Waveform computation mode performs internal computation differently from other
measurement modes. Therefore, some functions such as trend and bar graph displays
on the screen, integration, and storage function cannot be used in this measurement
mode. In addition, some measurement functions such as harmonic measurement
and impedance cannot be carried out. For a list of functions with limitations and
measurement functions that cannot be measured, see appendix 10 and 11 in the
User's Manual IM WT3001E-01EN.
Note
In waveform computation mode, TYPE 3 cannot be selected for the equation of the apparent or
reactive power. If TYPE3 is selected and you select waveform computation mode, the equation
switches to TYPE1. For details on the type of equations, see section 2.5 and 5.9 in the User's
Manual IM WT3001E-01EN.
• Rms Values of Voltage U and Current I
The rms values of the voltage U and current I that are measured in the waveform
computation mode are normal measured values. For details on the normal measured
value, see "Relationship between the Rms Values of Voltage U/Current I and
Measurement Modes" in section 7.1.
between phases S and T)
of phase T)
IM WT3001E-51EN
Advertisement
Table of Contents
