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9.7 Cycle Automatic Variable Function
If deviation between EVT
value and measured value enters EVT
cycle variable
range, the proportional cycle will be automatically extended in accordance with the
deviation.
Proportional action OFF time will be extended, and ON / OFF ratio will be adjusted.
However, if EVT
cycle extended time is set to 0 (zero), this function will be disabled.
(Fig. 9.7-1)
Large
EVTx
EVTx cycle
Small
0 sec.
ON time
OFF
ON
C
ON
tf1
OFF
ON
tf2
OFF
Ctf1
C
C
C
C
C
OFF time
?
C
C
C
OFF
ON
Deviation
Control direction
EVTx proportional band
Cycle fixed range
EVTx cycle variable range
Time
(Seconds)
extended time
proportional cycle
OFF time
ON time
Cycle delay time (Ctf1, Ctf2)
Proportional cycle of
usual P control action
Usual P control action
EVTx output
Cycle is constantly fixed.
Usual P control action
EVTx output
EVTx cycle variable range
Action when EVTx cycle variable range is set.
C: EVTx proportional cycle
Ctf2
Ctf1, Ctf2: Cycle delay time
tf1, tf2: Extended OFF time
EVTx value
