Flow Rate Limiter - YASKAWA U1000 iQpump MATRIX Drive User Manual

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Flow Rate Limiter

The flow rate limiter function reduces speed when the flow rate reaches a high or low limit to reduce system pressure.
The drive reduces the output speed to limit the flow rate. Parameter P6-27 determines whether the Flow Rate Limit Level acts
as a High Limit (P6-26 = 1) or a Low Limit (P6-26 = 2).
When P6-26 is set to 1 (Enabled), the output speed is reduced when the Flow Rate rapidly increases or rises above the level
set in P6-27.
When P6-27 is set to 2 (Enabled – Low Limit), the output speed is reduced through a PI controller when the Flow Rate rapidly
decreases or falls below the level set in P6-27. The output speed is lower-limited to the greater value between the Minimum
Pump Speed (P1-06) or Thrust (P4-12), plus the Minimum Output Frequency (E1-09).
Parameters P6-28 (Proportional Gain) and P6-29 (Integral Time) adjust the responsiveness of the PI controller.
Flow Limit Start Delay (P6-30) sets the length of time that the drive will wait before activating the Flow Rate Limiter at Start.
Note: When the Flow Limit Start Delay (P6-30) timer expires, the output speed may rapidly decrease depending on the Flow Rate level compared
to the Flow Limit (P6-27). Be sure to set P6-30 long enough to allow the system to stabilize the Flow Rate.
n Total Accumulated Volume and Delta Accumulated Volume Monitors
Monitors U1-84 to U1-87 represent the Total Accumulated Volume as shown below:
Accumulated
Monitor U1-88 provides the same information in a single display. The decimals are dropped when P6-16 is set to 1 to display
in gallons. When the value being displayed is more than 99999 gal or units are in A-F (P6-16 = 2), the display will initially
show "U1-88 = - - gal" or "U1-88 = - - A-F" and immediately switch over to the full value with the monitor number removed.
The unit and commas may be removed depending on the size of the value. Note that the unit is always displayed in the Monitor
Title Text (Total Vol (gal) or Total Vol (A-F)).
Monitor U1-89 shows the volume accumulated with the values stored in parameters P6-36 to P6-39 (Delta Volume) as the
starting point. The display operates the same as U1-88, except that it can be signed and switched to full value display when
above 9999 gal or below -9999 gal.
Note: When the units are in Acre-feet, the number of decimal places decreases by 1 when the value is above 9,999,999,999.9999 A-F or below
-9,999,999,999.9999 A-F.
The value for U1-89 is equal to the Total Accumulated Volume (U1-88/U1-84 to U1-87) – Starting Delta Volume (P6-36 to
P6-39).
Starting Delta Volume parameters P6-36 to P6-39 can be populated manually by individually setting each parameter. Setting
P6-35 to 1 (Set) will write the current Total Accumulated Volume (U1-88/U1-84~U1-87) to the parameters, while setting
P6-35 to 2 (Reset) will write 0 to these parameters.
YASKAWA TOEPYAIUPW01A YASKAWA AC Drive - U1000 iQpump Matrix Drive User Manual
U1-84
=
Volume
4.6 U1000 iQpump Presets and Functions
U1-85
U1-86 U1-87
gallons or
acre-feet
127
4