Mitsubishi q64rd, User Manual

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MELSEC-Q
3 SPECIFICATIONS
(3) Primary delay filter
By setting a time constant, excessive noise is eliminated and smoothed
temperature value can be output. Depending the time constant, the degree of
smoothness is changed.
The relational expression between the time constant and measured temperature
value is shown below.
[In the case of n=1]
Yn=1
[In the case of n=2]
Δ t
Yn = Xn -
1
+
Δ t + TA
(Xn - Xn -
1
)
[In the case of n 3]
Δ t
Yn = Yn -
1
+
Δ t + TA
(Xn - Yn -
1
)
Yn: Current measured temperature value Δ t: A/D conversion time (0.04ms)
N : Sampling count TA: Time constant (s)
Yn-1: Preceding measured temperature value
Xn: measured temperature value before smoothing
* Conversion completion flag (buffer memory address10: Un\G10) turns on at n
2.
[Example] When the temperature input value is changed from 25.000 to 26.000
In the time constant setting of 1000ms (1s) measured temperature
value is changed as shown below.
At 1000ms (1s) after the temperature input value is changed to
26.000 , the measured temperature value reaches 63.2% of the
value output in the case of selecting the sampling processing.
25
25.2
25.4
25.6
25.8
26
26.2
0 1000 2000 3000 4000 5000 6000
Elapsed time (ms)
(
)
25
25.2
25.4
25.6
25.8
26
26.2
Temperature input value Measured temperature value
T
em
pera
ture input
v
alue
M
e
asured t
em
pe
ra
ture valu
e