YASKAWA iQpump1000 User Manual page 173

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Pre-Charge Function with One Lag Pump
The pre-change function is designed to start a pumping system in a controlled manner. Rather than turning on the PI loop
immediately at start up, the pre-charge function operates at a fixed speed to pre-fill the piping or storage tank before switching
to PID control. This prevents the PI loop integrator from building up unnecessarily and also allows for a soft pressurization
and fill of the system.
When an "auto" run command is issued or when waking up from the sleep state, the drive will check to see if it should perform
a pre-charge operation. If so, it will ramp up and run at the pre-charge frequency. Some of the pump protective functions are
disabled during pre-charge operation.
The drive will exit the pre-charge function when any of the below conditions are met:
• The process feedback level reaches the pre-charge level (P4-01)
• A multi-function digital input programmed for a Low Water Level switch deactivates (H1-oo = 8F)
• The pre-charge timer expires (P4-03).
n Required Control Wiring
No control wiring is required. An optional Low Water Level switch can be used to turn off the pre-charge function. Wire the
switch into one the drive digital inputs and program the corresponding H1-oo parameter to 8F (the switch is normally open
and closes during low water level).
n Start Up Procedure
1.
Set all other parameters required for the application such as PI control loop, sleep, motor, and I/O parameters.
However, this function can be used in conjunction across a wide range of applications using a PI control process loop.
2.
Set the pre-charge level in parameter (P4-01). This is the process feedback level (PSI, depth, etc.) that must be
achieved before the pre-charge function will turn off.
3.
Set the pre-charge frequency reference in parameter P2-02. This is the frequency that the drive will run at during pre-
charge. Set this value to reasonable speed that is above the minimum pump speed (P1-06) and close to the average
running frequency of the drive controller.
4.
Set the pre-charge timer in P4-03. When the drive goes into pre-charge mode, no low-water switch is wired to the
drive, and if the pre-charge level (P4-01) cannot be obtained, the drive will exit the pre-charge function after the P4-03)
time and begin normal PI control
5.
A multi-function digital input can be wired to and programmed for Pre-charge Disable if required (H1-oo = 8C).
Parameter P1-30 configures the switch type (0: Normally Open, 1: Normally Closed).
6.
A multi-function digital output can be wired to and programmed to close whenever the pre-charge function is active
(H2-oo = A4).
n Conditions for Entering Pre-charge Mode
• Drive Ready or Sleeping (run command, not faulted, not in program mode).
• NOT in HAND Mode
• "Disable Pre-Charge" digital input NOT closed.
• Pre-charge time set greater than zero (P4-03 > 0)
• If the Pre-charge level is greater than zero (P4-01 > 0) and the PID feedback is below the P4-01 level (Forward acting PID,
b5-09 = 0).
• If the Pre-charge level is greater than zero (P4-01 > 0) and the PID feedback is above the P4-01 level (Reverse acting PID,
b5-09 = 1).
n Operation During Pre-Charge Mode
• Drive will run at the Pre-Charge frequency (P4-02).
• The PID controller is disabled.
• The HOA keypad will display the message "Pre Chg Mode – Pre-chg Active".
• The pre-charge digital output (H2-0o = A4) will close
• If the Pre-Charge frequency (P4-02) is set less than minimum pump speed (P1-06), an alarm "Freq. Ref < Pump Min P1-06"
will be displayed and the drive will run at the minimum pump speed.
n
Conditions for Exiting the Pre-Charge Mode
• When Pre-Charge timer expires (P4-03). The drive will always exit after the pre-charge timer expires.
YASKAWA TOEP YAIP1W 01F YASKAWA AC Drive - iQpump1000 User Manual
4.6 iQpump Presets and Functions
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