Grundfos DDC Data Booklet

Functions
18
SMART Digital S
3
Pressure monitoring
Applies to DDA-FC/FCM
The integrated pressure sensor measures the actual
pressure of the system, which is shown in the display.
A maximum pressure can be set. If the pressure in the
system exceeds the set maximum (e.g. caused by a
closed valve), the pressure monitoring function stops
the dosing process immediately. As soon as the
backpressure falls below the set maximum, the dosing
process is continued. In case the pressure drops below
the minimum limit (e.g. caused by a burst discharge
line) the pump stops and major chemical spills are
prevented.
Pressure setting range
* Can be either set as a warning (pump keeps running) or as an
alarm (pump stops)
** The adjustable max. pressure is equivalent to the max. operating
pressure plus 1 bar
Flow measurement
Applies to DDA-FCM
The pump can precisely measure and display the
actual dosing flow. Via the analog 0/4-20 mA output,
the actual flow signal can easily be integrated in any
process control system, without needing any additional
measurement equipment.
The Flow measurement function is based on an
indicator diagram as described in FlowControl
(page 16). Accumulating the length of each discharge
stroke phase and multiplying it with the stroke
frequency results in the displayed actual flow.
Any malfunctions, such as air bubbles or lower
backpressure, will result in a reduced or increased
actual flow rate. When the AutoFlowAdapt function
(page 18) is activated, the pump compensates these
influences by correcting the stroke speed.
AutoFlowAdapt
Applies to DDA-FCM
When activating the AutoFlowAdapt function even
environmental changes will be compensated, so that
the required target flow rate will be achieved.
The integrated AutoFlowAdapt makes additional
monitoring and control devices redundant.
The AutoFlowAdapt function is based on:
• FlowControl: malfunctions are detected
• Pressure monitoring: system pressure changes are
detected
• Flow measurement: deviations in the target flow are
detected.
Examples:
• FlowControl detects air bubbles in the system.
Due to a special motor drive strategy and a certain
speed increase, the pump will try to keep the flow
rate constant. This is especially important when
dosing degassing liquids.
• In general, increasing system pressure reduces the
stroke volume whereas falling system pressure
increases the stroke volume. The AutoFlowAdapt
function compensates this by automatically and
continuously adapting the motor speed.
Despite fluctuating system pressure, dosing
accuracy is maintained.
Pump type
Fixed min. pressure
[bar]*
Adjustable max. pressure
[bar]**
DDA 7.5-16 < 2 3 ... 17 (default)
DDA 12-10 < 2 3 ... 11 (default)
DDA 17-7 < 2 3 ... 8 (default)
DDA 30-4 < 2 3 ... 5 (default)

Grundfos DDC Specifications

General

Brand	Grundfos
Model	DDC
Category	Water Pump
Language	English