■Operation Procedure Panel on PCB Cover
As Fig. 46 shows, on PCB cover, the operation flow from “000
Actuator type” to “C00 Calibration” is described in simplified
form for customer’s reference. For details of each parameter
setting, see “■Parameter Code Detail” in this operation
manual. Keep the manual accessible for reference.
Improved Controllability
PID constant of this positioner is automatically set during calibration. However, operation speed is
delayed or controllability becomes unstable due to the used actuator size. These symptoms can be
improved by changing PID constant. When adjustment is made, please refer the table below to
keep the specified range so that the operation does not become unstable
*1
.
Time to reach target
value is slow
①Increase the easy adjustment integral time (I constant)
by one level within the range that overshoot
*2
does not
occur.
② Increase the easy adjustment proportional gain (P
constant) by one level within the range that
undershoot
*3
does not occur to the valve characteristic.
-Overshoot may occur
-Hunting
*4
may occur
Hunting with small
fluctuation is generated
with high frequency.
Decrease easy adjustment of proportional gain
(P constant) and integral time (I constant) level by level.
-Operation might be
delayed
Hunting with large
fluctuation is generated
with low frequency.
Increase simple adjustment of proportional gain
(P constant) level by level.
Stick-slip occurs during
control
Decrease easy adjustment proportional gain (P constant)
and differential time (D constant) level by level.
-Operation might be
delayed
1: Although PID of extracting and retracting direction can be set differently, smooth stop at desired position
may not be available if the value is difference.
2: The position temporarily exceed the target value when the input current is supplied.
3: Value temporarily falls below the target value after overshoot.
4: Position is not well controlled to the target value, and the actuator open degree repeat too large and too
small.
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