11
English (US)
6. Control functions
6.1 Internal control principles
ALPHA2 26-99 circulator pumps automatically
control the differential pressure by adjusting the
pump performance to the actual heat demand,
without the use of external components.
Two different control modes are available:
6.1.1 GRUNDFOS AUTOADAPT
The Grundfos AUTOADAPT function enables
the circulator to control the pump performance
automatically within a defined performance
range.
•
Adjusting the pump performance to the size
of the system.
•
Adjusting the pump performance to the
variations in load over time.
Two different control modes are available for
Grundfos AUTOADAPT:
6.2 External control principles
6.2.1 0-10 VDC
ALPHA1 26-99 circulators are externally speed-
controlled by an analog 0-10 V DC signal.
The pump requires a 0-10 V signal on the signal
port to control the speed of the pump. The pump
will run at its minimum speed if the signal fails
(cable break).
Profile R
Fig. 6
Profile R
Proportional Pressure
The differential pressure increases at
increased flow.
Constant Pressure
The differential pressure is constant.
Proportional Pressure
AUTOADAPT
In proportional pressure
AUTOADAPT, the circulator is set to
proportional-pressure control.
Constant Pressure AUTOADAPT
In constant pressure AUTOADAPT,
the circulator is set to constant-
pressure control.
TM
07
04
3
9
50
17
TM
0
7
0
78
4 0
518
U [V]
Pump status
0.5 < U
≤
1
Standby (Stop)
1 < U
≤
2
Hysteresis
2 < U
≤
3
Min. speed
3 < U
≤
10
Speed between Min. and Max.
470 R
36 V
0-10 V
PWM
Signal input
Signal output
Signal ref.
0.5
4
5
U[V]
1
2
3
9
6
7
8
10
Max.
Min.
Stop
Содержание TM07 2122 2818
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