15-10
IM 253710-01E
Explanation
The following two types of filters are available on the motor module.
Selecting the line filter
This filter is inserted into the circuit (CH7 and CH8) that measures the revolution
sensor and torque meter signals. It eliminates harmonic noise. The cutoff frequency
can be selected from the list of choices below. Selecting OFF disables the filter.
OFF, 100Hz, and 500Hz.
Selecting the zero crossing filter
This filter is inserted only into the frequency measurement circuit. Zero crossing
refers to the point at which the input signal crosses the center level of the amplitude.
This filter is used to accurately detect the zero cross point. This instrument detects
the zero crossing point with a hysteresis of approximately 3.5% of the specified input
range of the revolution sensor signal or torque meter signal (see section 15.2). The
cutoff frequency can be selected from the list of choices below. When the zero
crossing filter is OFF and the line filter (above) is ON, the cutoff frequency specified by
the line filter is used as a zero crossing filter.
OFF, 100Hz, and 500Hz.
Note
•
The line filter and zero crossing filter functions of CH7 do not operate when the signal type of
the revolution sensor is set to [Pulse].
•
The input filter can be used to remove the noise from the signal when the revolution sensor
signal or torque meter signal is used as a PLL source (see section 6.4) for harmonic
measurement.
15.3 Selecting the Input Filter