KSB PumpDrive 2 - Sensorless Flow Rate Control; Parameters for Sensorless Differential Pressure Control

8 Commissioning/Shutdown
81 of 212
PumpDrive 2
NOTE
To facilitate sensorless differential pressure control, all parameters of the pump
characteristic curves (3-4-1, 3-4-3-1 to 3-4-3-22) and the inside pipe diameters at the
pressure measuring points (3-5-2-1 and 3-5-2-2) must have been entered.
Table55: Parameters for sensorless differential pressure control
Parameter Description Possible settings Factory setting
3-6-1 Type of Control
Selecting the control method. The
controller is deactivated when OFF (Open-
loop Control) is selected.
Differential Pressure (Sensorless) Dependent on pump
8.7.1.2.4 Sensorless flow rate control
Sensorless flow rate control enables control to achieve a constant flow rate of the
pump or multiple pump system without the use of a flow rate sensor. The method is
based on the characteristic curves of the pump. Steep power curves are conducive to
high process accuracy. It is activated by setting the Type of Control parameter (3-6-2)
to Flow Rate (Sensorless), with flow rate estimation being active (3-9-8-1 set to ON).
(ðSection8.6,Page70)
The time response of the control process is influenced not only by the designated
control parameters (3-6-4-2 to 3-6-4-4), but significantly by the Attenuation of Flow
Rate Estimation parameter (3-9-8-2). The larger and more "sluggish" a hydraulic
system is, the higher the value that must be assigned to this parameter. The value
should roughly coincide with the system's response time. The response time of the
system refers to the time that lapses after a change in speed until the flow rate
exhibits almost no change at all.
NOTE
To facilitate sensorless flow rate control, all parameters of the pump characteristic
curves (3-4-1, 3-4-3-1 to 3-4-3-22) and the inside pipe diameters at the pressure
measuring points (3-5-2-1 and 3-5-2-2) must have been entered.
NOTE
For power curves with sections of the curve being constant over the flow rate (flat
characteristic curve), signals must be made available for the suction pressure and
discharge pressure of the pump.