Savch S2800 Series, Руководство пользователя

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Proportion adjustment (P): when there is deviation between feedback quantity and set
quantity, the adjusted quantity must be proportional to deviation. If the deviation is invariable,
the adjusted quantity is also constant. The proportion adjustment can reflect the variation of
feedback rapidly. But proportion adjustment alone can't achieve reference control. The
greater the proportion gain is, the faster the adjusting speed of system comes. And the over
great of proportion gain will cause oscillation.
The adjusting step is as follows: first, set a long integral time and make differential time zero,
let system run only with proportion adjustment only. Then change the set quantity and
observe the stable deviation (static deviation) of feedback signal and set quantity. If the
static deviation is in the variation direction of set quantity (e.g., When increase set quantity,
the feedback quantity is always smaller than set quantity after system stabilization),
increase the proportion gain continuously, decrease the proportion gain on the contrary.
Repeat above steps until the static deviation is small enough (It is difficult to clear static
deviation).
Integral time (I): when there is deviation between feedback quantity and set quantity, the
output adjusted quantity accumulated continuously. If the deviation still exists, the adjusted
quantity will increase continuously until no deviation receives. The integral adjuster can
eliminate the static deviation efficiently. If the integral adjustment is too strong, repeated
over-adjustment will occur, which makes system unstable until oscillation produced.
The oscillation characteristics is as follows. The feedback signal wobbles up and down on
set quantity. The wobble width increases gradually until oscillation. The adjustment of
integral time parameter is from big to small,adjusting integral time gradually,observing the
effects of system adjustment until the sped of system stabilization meets the requirement.
Differential time (D): When the deviation between feedback quantity and set quantity varies,
input the adjusted quantity are proportional to change rate of deviation. The quantity only is
affected by variation direction and variation quantity, while having nothing to do with its
deviation and value.
When the feedback signal varies, the differential adjustment will adjust according to the
varying tendency to suppress the variation of feedback signal. Please use differential adjust-
ment carefully. The differential adjustment would easily enlarge the system interference,
especially the interference on greater changing frequency.
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Sampling period (T)
Setting range 0.01~100.00s[s]
10-07
Factory setting
0.10
Sampling period (T): it refers to the sampling period of feedback quantity. The adjuster
computes once in every sampling period. The longer the sampling period is, the slower the
response will be.
Limitation of PID control deviator: PID system output value corresponds to the maximum
deviation allowed for closed ring set value. As shown in the diagram below, The PID
adjuster stops adjusting within the deviation limitation. The proper setting of this function
code can adjust the accuracy and stability of PID system.
Limitation of PID control deviator
Setting range 0.0~100.0[%]
10-08
Factory setting
0.0