Yaskawa iQpump Controller Programming Manual - Manual (Page 254)

254 YASKAWA TM.iQp.07 iQpump Controller Programming Manual
Table 121 Message
This mode monitors both the feedback level and the output frequency to determine if de-staging is needed. the output frequency of the
lead drive drops below the P9-13 level and the delta feedback (feedback - setpoint) has exceeded the P9-14 level for the time set in
P9-15, then a de-stage request is issued if this is not the only drive running.
◆ iQpump MEMOBUS / Modbus Layered Sequencing and Control
■ MEMOBUS / Modbus Layered Sequencing and Control
Several applications of multiplexed drives require priority sequencing and run restrictions. For example, a drive designated as a back-up
pump would be restricted for alternation only or will have a low run priority. A jockey pump would be designated as a first drive only and
may never be allowed to alternate with a bigger-sized pump. Because of the variety of applications, a flexible set of parameters need to
complement the Multiplex and Alternation parameters.
• Provide more staging control over the MEMOBUS / Modbus Multiplex and Alternation features.
• Ability to restrict drives to first drive only, alternation only or either one.
• Provide a way to return Lead Drive control to a drive with higher priority.
■ Function Description:
<0034>
Setting Allow Net Run P9-20 = 0 allows that drive to respond to all network run commands (first drive, stating, alternation). When
P9-20 = 1, the drive is limited to being either the first drive or for alternation. When P9-20 = 2, the drive can only be a first drive. When
P9-20 = 3, the drive is only available for alternation. Note that when Alternation Mode P9-04 = FIFO Auto and there are 2 drives or more
running, the iQpump MEMOBUS / Modbus Network does not actually alternate a drive in. It simply removes the expired first drive and
allows the iQpump MEMOBUS / Modbus Multiplex feature to stage a new drive. Explicit alternation still happens in FIFO Auto when
there is only one drive running at time of alternation.
Setting Run Priority P9-21 the same for all drives on the iQpump MEMOBUS / Modbus Network obviously nullifies the functionality.
Drives will simply use P9-01 at this point to select the next lead drive.
By setting P9-21 differently for a drive on the iQpump MEMOBUS / Modbus Network, sequential lead drive selection can be achieved.
Drives with the same P9-21 level will use the P9-01 parameter to determine the next lead drive.
As a way to give First Drive (and Lead Drive) control back to the drive with the highest priority level P9-21, the Lead Swap @ Sleep
Time P9-24 can be set on the other drives (with a lower priority level) so that if the drive sleeps continuously for the time set, the control
will be passed to the higher priority drive.
Message Display Description Cause Countermeasures
Net Start Dly P9-29
Active
System was on the Pump Off
Network State and a drive has
been put on Auto Mode. The iQpump MEMOBUS / Modbus Network is
waiting for the
P9-29 timer to elapse.
Change P9-29 timer.