Yaskawa iQpump Controller Programming Manual - Manual (Page 39)

YASKAWA TM.iQp.07 iQpump Controller Programming Manual 39
Figure 1.30
Figure 30. Loss of PI Feedback Feature
◆ b5-17 PI Accel / Decel Time
Setting Range: 0.0 ~ 25.5 s
Factory Default: 0.0 s
This is a soft start function that is applied to the PI Setpoint analog input. Instead of having nearly instantaneous changes in signal levels,
there is a programmed ramp applied to level changes. When changing setpoints the error can be limited by gradually ramping the setpoint
through the use of parameter b5-17.
◆ b5-32 Integrator Ramp Limit
<0034>
The Integrator Ramp Limit provides a way to tune the PI loop so that it is less reactive to sudden spikes and dips in the feedback signal.
Sometimes in a pressure regulated system with a very long piping system, pressure waves can develop which without this feature, can
cause instability in the PI controller.
This feature only applies to the drive’s standard PI Loop. It will not be applied to the PI Loop associated with water level control (Well
Draw Down Control).
Function Description
<0034>
Integrator Ramp Limit.
When the Integrator Ramp Limit is enabled, the PI Integrator is limited to +/- the b5-32 value of the soft starter output (output frequency
without slip compensation). A b5-32 setting of zero disables this feature and the integrator is allowed to operate normally.
Table 14 Related Parameter
Parameter
No.
Addr.
Hex
Parameter Name
Digital Operator Display
Description
Setting
Range
Factory
Setting
Menu
Location
b5-32 85F
Integrator Ramp Limit
Int Ramp Lim When set to a value greater than zero, the PI Integrator is forced to be
within +/- this amount of the soft starter output 0.0 ~
10.0 Hz
0.0 Hz Programming
Measured
Feedback
T
t
Feedback
Loss Output
T
b5-13
T = b5-14
Feedback
Loss Digital Output
ON (CLOSED)
OFF (OPEN)
TIME