First-order lag filter, First-order lag filter -26 – Yokogawa PC-Based MX100 User Manual
Page 71
2-26
IM MX100-01E
First-Order Lag Filter
For noise sources other than power supply noise, the MX100 is equipped with a first-
order lag filter having output characteristics indicated in the figure below against step
input. The time constant of the first-order lag filter can be selected on the PC software
(MX100 Standard Software, MXLOGGER (sold separately), or the API for the MX100/
DARWIN (sold separately)).
Step input
63.2% of the output value
Time constant
0%
100%
Output characteristics
Measurement
Interval (s)
Selectable Time Constants (s)
n=5
n=10
n=20
n=25
n=40
n=50
n=100
0.01
0.05
0.1
0.2
0.25
0.4
0.5
1
0.05
0.25
0.5
1
1.25
2
2.5
5
0.1
0.5
1
2
2.5
4
5
10
0.2
1
2
4
5
8
10
20
0.5
2.5
5
10
12.5
20
25
50
1
5
10
20
25
40
50
100
2
10
20
40
50
80
100
200
5
25
50
100
125
200
250
500
10
50
100
200
250
400
500
1000
20
100
200
400
500
800
1000
2000
30
150
300
600
750
1200
1500
3000
60
300
600
1200
1500
2400
3000
6000
If the first-order lag filter is applied to the input signal, low-pass filter frequency
characteristics shown in the figure below are attained.
Cutoff band
0dB
–3dB
Pass band
Frequency
Attenuation
Cutoff frequency
If the time constant of the first-order lag filter is set long, the cutoff frequency is lowered,
and frequency bandwidth that can be rejected is widened. Set an appropriate time
constant according to the frequency of the noise you wish to reject.
2.7 Measures against Noise on the MX100