KSB PumpDrive 2 - Example of Open-Loop Control Mode Via Control Panel; Closed-Loop Control Mode; Overall Structure of the Process Controller; Selecting the Type of Control

8 Commissioning/Shutdown
74 of 212
PumpDrive 2
Table48: Example of open-loop control mode via control panel
Parameter Description Possible settings Refers to Factory setting
3-6-1 Type of Control
Selecting the control method. The
controller is deactivated when OFF
(Open-loop Control) is selected.
OFF (Open-loop Control) - Dependent on pump
3-2-2-1 Minimum Motor Speed 500 rpm 3-11 500 rpm
3-2-2-2 Maximum Motor Speed 3000 rpm 3-11 2100 rpm
1-3-1 System Start / Stop
This function is used to start the
system.
Start - Stop
1-3-3 Control Value (Open-loop
Control)
Configurable control value for
speed in open-loop control mode
2000 rpm - 500 rpm
8.7.1.2 Closed-loop control mode
The frequency inverter has a process controller to detect and adjust or compensate
for changes in hydraulic processes. Controlled variables such as discharge pressure,
differential pressure, flow rate and temperature are recorded and compared with the
setpoint specified. Based on the current control deviation, a new control variable is
calculated that is implemented as the new speed for the drive.
Overall structure of the process controller
3-6-3
3-6-2
3-6-1
3-6-4-2
3-6-4-3
3-6-4-4
3-6-4-8
3-6-4-6
3-6-4-5
Controlled variable
Control deviation
+
-
+
+
Setpoint
Control variable
Operating point
Setpoint ramp time
Drive and
hydraulic process
Setpoint ramp
Process controller
Fig.58: Overall structure of the process controller
The hydraulic process to be controlled, influenced by the speed of the frequency
inverter, represents the controlled system. The measured controlled variable, or in
the case of sensorless differential pressure control, the internally calculated
controlled variable, is subtracted from the setpoint to form the control deviation. The
control deviation is supplied to the actual process controller. The time taken to
achieve the setpoint can be prolonged via a setpoint ramp.
Selecting the type of control
To activate the process controller, the type of process to be controlled must be
selected via the Type of Control parameter (3-6-1). When OFF (Open-loop Control) is
selected, the process controller is deactivated and the frequency inverter runs in
open-loop control mode.