KSB PumpDrive 2 - Sensorless Differential Pressure Control

8 Commissioning/Shutdown
80 of 212
PumpDrive 2
the frequency inverter. The setpoint specification is made as an external setpoint
signal (4 - 20mA) via analog input1. For the desired setpoint of 6.7bar, 10.7mA
must be applied at analog input1. The system start is activated by the System Start /
Stop parameter (1-3-1). The frequency inverter starts as soon as it is set to automatic
or manual mode and the enable is given via DI-EN.
Table54: Example of closed-loop control mode with setpoint specification via external setpoint signal
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 Dependent on pump
3-11-2-1 Minimum Pressure
Minimum limit of measuring range
0,00 -1,00 bar
3-11-2-2 Maximum Pressure
Maximum limit of measuring range
10,0 1000,0 bar
3-11-2-3 Pressure Unit
Configurable unit for pressure 1
bar bar
3-8-1-1 Analog Input 1 Signal
Sensor signal at analog input 1
4…20mA OFF
3-8-1-2 Analog Input 1 Function
Function of analog input1. Internal
operating values cannot be used as an
actual value source.
Setpoint/Control Value (Auto) OFF
3-8-1-3 Analog Input 1 Lower Limit 0,00 0,00
3-8-1-4 Analog Input 1 Upper Limit 10,00 100,00
3-8-2-1 Analog Input 2 Signal
Sensor signal at analog input 2
4…20mA OFF
3-8-2-2 Analog Input 2 Function
Function of analog input2. Internal
operating values cannot be used as an
actual value source.
Differential Pressure OFF
3-8-2-3 Analog Input 2 Lower Limit 0,00 0,00
3-8-2-4 Analog Input 2 Upper Limit 10,00 100,00
1-3-1 System Start / Stop
This function is used to start the system.
Start Stop
NOTE
The System Start/ Stop parameter (1-3-1) must be set to Stop if the system start
takes place via the digital input.
8.7.1.2.3 Sensorless differential pressure control
Sensorless differential pressure control enables control to achieve a constant
differential pressure of the pump without the use of pressure sensors in a single-
pump configuration. The procedure is based on the characteristic curves of the pump.
Steep power curves are conducive to high process accuracy. The process is suitable to
a limited extent if sections of the power curve are constant over the flow rate or the
pump operates outside the permissible operating range. It is activated by setting the
Type of Control parameter (3-6-1) to Differential Pressure (Sensorless). Setting the
setpoint (ðSection8.6,Page70) .