Yaskawa iQpump Controller User Manual - Manual (Page 241)

G.3 Well Draw Down Function
YASKAWA TM.iQp.06 iQpump Controller User Manual 241
G.3 Well Draw Down Function
The Well Draw Down function in parameter P8-01 allows the iQpump drive to deliver water at a constant pressure as long as the ground
water remains above the level set in parameter P8-03.
If the ground water level drops to the Water Level Setpoint (P8-03), the iQpump drive will switch from constant pressure regulation to a
level regulation and continue to supply water at the recharge rate of the well
If the water level of the well continues to drop, parameter P8-04 will force the iQpump drive to go to sleep. The iQpump drive will
remain asleep until the water level rises to the Wake-Up Water Level (P8-05) and will then restart pumping.
Once the water level rises above the Minimum Water Level (P8-04), parameter P8-01 will resume maintaining constant pressure.
◆ Related Parameters
◆ Well Draw Down Function Set-Up
■ 1. Select Proper Depth-Sensing Transducer
Select a depth-sensing transducer with the transducer element, electrical connections, and connecting cable sealed and safe for liquid
submersion. Additionally, the sensor must include a vent tube running the length of the electrical conductors to compensate for changes
in barometric pressure to ensure accurate feedback with changing weather patterns.
It is also important to select a depth-sensing transducer with electrical conductors installed by the manufacturer at the length specified by
the installer to guarantee that the manufacturer can calibrate the transducer to compensate for any voltage drop across the conductor
length.
The maximum length for the pressure transducer leads is 50 m (164 ft); in lengths exceeding 50 m the voltage drop will cause inaccurate
feedback. Do not use a standard pressure transducer for level control because many wells exceed 50 m depth and the user must include a
transducer calibrated to compensate for the resistance of the wire length from the transducer to the iQpump drive.
Select a range of depth that closely matches the application range. There is not one depth range correct for all applications, especially
regarding depth calculations sensitive to small changes in feedback. If the range is too large, accuracy will be compromised.
■
2. Install Depth-Sensing Pressure Transducer
Separate the pressure transducer leads from the motor leads as the feedback transducer may be sensitive to the iQpump drive motor PWM
waveform.
Parameter Number Parameter Name
d1-01 Setpoint Reference 1
H3-02 Terminal A1 Gain Setting
H3-03 Terminal A1 Bias Setting
P1-05 Start Level Delay Time
P1-06 Minimum Pump Frequency
P2-03 Sleep Delay Time
P4-05 Thrust Bearing Frequency
P8-01 Pressure and Level Control Select
P8-02 Water Level Scaling
P8-03 Water Level Setpoint
P8-04 Minimum Water Level
P8-05 Wake-Up Water Level
P8-06 Level Control Minimum Speed
P8-07 Low Level Detection
P8-09 Low Level Behavior
U1-01 Auto Setpoint Reference
U1-98 Water Level