Mitsubishi Electric MELSEC iQ-R User Manual page 40

Setting example
The following shows the setting example of a digital filter.
■Example 1
The following describes an example under the following conditions with a low pass filter.
• Operation mode: Normal mode (medium speed: 10s/CH)
• Channels to be used: CH1
• Conversion cycle: 10s (Sampling frequency: 100kHz)
• 'CH1 LPF Pass band edge frequency' (Un\G560): 1400 (Hz)
• 'CH1 Attenuation band width' (Un\G568): 1300 (Hz)
• The frequency of analog inputs is changed from 1000Hz to 4000Hz, and 4000Hz to 10000Hz to input a SIN wave.
digit
(1) 0
1000Hz
0 (3)
digit
(5)
(2) 0
0
digit: Digital output value
t: Time (ms)
(1) Input waveform
(2) Waveform after the digital filtering
(3) Frequency that passes through
(4) Frequency to be attenuated
(5) Response time (Conversion cycle (10s)  Filter degree (255)
*1 The filter degree is calculated with the following formula.
= 3.3  (1000000  10)  1300
= 253.846
= 254 (Value after the decimal point is rounded up.)
Because the calculation result is an even value, add 1 so that the value becomes an odd value.
= 254 + 1
= 255
1 FUNCTIONS
38
1.5 A/D Conversion Method
4000Hz 10000Hz
(4)
*1
= 2.55ms)
(4) t
t