Yaskawa iQpump Manual Supplement - Manual (Page 44)

44 YASKAWA TM.iQp.10 iQpump Technical Manual Supplement
12 Speed Follower Deceleration Time Switchover <0036>
12 Speed Follower Deceleration Time Switchover <0036>
‹ Overview
The current iQpump Speed Follower will attempt to match the speed of the Lead Drive after the Lag Drive Fixed Speed
Delay.
Consider a scenario wherein the system needs help from an idle drive to maintain system pressure. When the idle drive is
called to run, the difference between the set-point and the feedback may be too small to make the drive accelerate faster.
In the case of a system is configured with these settings:
• Set for Lag Drive Speed Follower
• Add Pump method is Frequency Reference
• Frequency Reference setting close to the maximum frequency
The system will drop the speed after the Lag Drive Fixed Speed Delay expires in order to follow the output frequency of
the previously idle drive. This transition may cause unwanted pressure drops. A longer deceleration time will be activated
on the lag drives when the system switches the drive that is being followed. The longer deceleration time will be effective
for a programmable setting, after which, the regular deceleration time is used.
Note: The Network Compatibility Mode parameter P9-99=1: B-Version 30035+ reflects support for drive software
version U1-14=30036 and nameplate PRG: 0036.
„ Functional Operation
If P9-05 = 3 (Follow Lead Spd), the lag drive will use the network information and the lead drive's output speed as its
frequency reference. The lag drive's final speed reference is affected by (Lag Follower Gain P9-30) and then by (Lag
Follower Bias P9-31).
Lag Drive Speed = ( Lead Drive Speed x Lag Follower Gain ) + Lag Follower Bias
When P9-33 > 0.0 sec, an alternate deceleration time (Lag Follower Decel P9-32) is used when the drive switches from
the latched speed (Lag Fixed Delay P9-07) to the new Lead drive's output frequency. The deceleration time is active for
the duration set in (Lag Followr Dtim P9-33), and will switch back to the regular deceleration rates when it expires.
Note: Parameter functionality stated below only applies when P1-01 = 3 (Memobus Network)
P9-32 Lag Follower Deceleration Time
P9-33 Lag Follower Deceleration Time Active Time
„ Related Parameters
Note: Parameter functionality stated below only applies when P1-01 = 3 (Memobus Network)
P9-05 Lag Drive Mode
Determines the function of the lag drive.
Range Description Default
0.0 ~ 1000.0 sec
When the P9-33 timer is running, and the drive is running as Lag Drive Speed
Follower (P9-05 = 3), then the deceleration time is set to this value.
60.0 sec
Range Description Default
0.0 ~ 360.0 sec
The P9-32 deceleration time is effective during this time window. The drive
will use the standard deceleration rates when it expires.
A setting of 0.0 sec will disable the Lag Follower deceleration time switching.
0.0 sec
Setting Description
0
Fixed Speed (factory default)
Runs at the P9-06 setting after the P9-07 time expires.