Grundfos ALPHA1 L Serie Instrucciones De Instalación Y Funcionamiento página 16

6.2.3 Constant curve or constant speed, I, II or III
At constant-curve or constant-speed operation, the pump runs at a
constant curve. The pump performance follows the selected
performance curve, I, II or III. See fig. Constant-curve/-speed curve
where II has been selected.
H
Constant-curve/-speed curve
The selection of the constant-curve or constant-speed setting
depends on the characteristics of the heating system in question.
6.2.4 Pump setting for one-pipe heating systems
Recommended and alternative pump settings:
Recommended control
System type
mode
Constant curve or constant
One-pipe
speed, I, II or III. See sec-
heating sys-
tion Constant curve or con-
tem
stant speed, I, II or III.
Related information
6.2.3 Constant curve or constant speed, I, II or III
6.2.5 Pump setting for domestic hot-water systems
Recommended and alternative pump settings:
Recommended control
System type
mode
Constant curve or con-
Domestic hot- stant speed, I, II or III. See
water system section Constant curve or
constant speed, I, II or III.
Related information
6.2.3 Constant curve or constant speed, I, II or III
6.2.6 Changing from recommended to alternative pump setting
Heating systems are relatively slow systems that cannot be set to
the optimum operation within minutes or hours.
If the recommended pump setting does not give the desired
distribution of heat in the rooms of the house, change the pump
setting to the shown alternative.
6.3 Control signal
The pump can be controlled via a digital low-voltage pulse-width
modulation (PWM) signal.
The square-wave PWM signal is designed for a 100 to 4,000 Hz
frequency range. The PWM signal is used to select the speed
(speed command) and as feedback signal. The PWM frequency on
the feedback signal is fixed at 75 Hz in the pump.
For instructions on how to set the connection, see section Setting
the PWM input signal.
Duty cycle
d % = 100 x t/T
Example Rating
U
T = 2 ms (500 Hz)
U
t = 0.6 ms
I
d % = 100 x 0.6 / 2 = 30 %
iH
16
Q
Alternative control
mode
No alternatives
Alternative control
mode
No alternatives
= 4-24 V
iH
≤ 1 V
iL
≤ 10 mA (depending on U )
iH
Example
t
U
IH
U
IL
PWM signal
Abbreviation Description
T Period of time [sec.]
d Duty cycle [t/T]
U
High-level input voltage
iH
U
Low-level input voltage
iL
I High-level input current
iH
Related information
7.1 Setting the PWM input signal
6.3.1 Interface
The pump's interface consists of an electronic part connecting the
external control signal to the pump. The interface translates the
external signal into a signal type that the microprocessor can
understand.
In addition, the interface ensures that the user cannot get into
contact with dangerous voltage if touching the signal wires when
power is connected to the pump.
Note: "Signal ref." is a signal reference with no connection to
protective earth.
1
2
3
4
BC847B
110R
100p
BC847B
Schematic drawing, interface
Pos. Description
1 Galvanic isolation
2 PWM output
3 Signal ref.
4 PWM input
5 Pump electronics
T
470R
TLP383
5
+
-
TLP2704