KSB PumpDrive 2 - Multiple Pump Systems; Improving Accuracy with Pressure Sensors Installed Close to the Pump; Flow Rate Estimation Parameters

8 Commissioning/Shutdown
97 of 212
PumpDrive 2
Improving accuracy with pressure sensors installed close to the pump
Signals sent from pressure sensors installed close to the pump can be used to improve
the accuracy of flow rate and head estimations. They should only be used, however,
if the pressure loss between the pump nozzle and pressure measuring point is
negligible both on the suction and discharge side (< 1% of the sensor measuring
range). If this requirement is not met, the Pressure Measuring Point Positions
parameter (3-5-2-4) must be set to the Distant from Pump value to deactivate the
influence of the pressure signals on flow rate estimation. Otherwise, the Close to
Pump default setting with activated accuracy improvement function applies. The
pressure measuring points must be described by parameters (refer to table on flow
rate estimation parameters).
Pressures that are recorded via analog inputs with the Suction Pressure_Internal,
Discharge Pressure_Internal or Differential Pressure_Internal function are only used
to improve the accuracy of the flow rate and head estimation. They are always
regarded as "close to pump" sensors, regardless of the Pressure Measuring Point
Positions (3-5-2-4) parameter.
Multiple pump systems
==
=
Fig.66: Conditions for improving accuracy with pressure sensors installed close to the
pump in multiple pump systems
The following additional conditions must be fulfilled for multiple pump systems in
which pressure measurements are only taken in collecting lines (or headers/
manifolds):
▪ All of the pumps are identical in design.
▪ Suction and discharge nozzles of the pumps have the same diameter (in-line
pumps).
▪ Suction and discharge-side collecting lines have the same diameter.
▪ The total flow rate is largely distributed equally across the individual pumps.
If these requirements are not met, the pressure signals may not be used to improve
the accuracy of the flow rate and head calculation. The Pressure Measuring Point
Positions parameter (3-5-2-4) must be set to the Distant from Pump value.
Table71: Flow rate estimation parameters
Parameter Description Possible settings Factory setting
3-9-8-1 Flow Rate Estimation
Activation of flow rate estimation
▪ OFF
▪ ON
ON
3-5-2-1 Inside Pipe Diameter, Suction Pressure
Measuring Point
Inside pipe diameter at the suction
pressure measuring point
0...1000mm 0,0mm
3-5-2-2 Pipe Diameter, Discharge Pressure
Measuring Point
Inside pipe diameter at the discharge
pressure measuring point
0...1000mm 0,0mm