Grundfos MAGNA3 Manual page 31

MAGNA3
The electrical signal for the input can be 0-10 V or 4-20
mA. You can change the selection of the electrical
signal (0-10 V or 4-20 mA) on the operating panel or
with Grundfos GO.
24V
Vcc
sensor
Fig. 42 Analog input for an external sensor or control
Max.
24 V DC
24V
22 mA
Vcc
0 - 10 V DC
Vcc
4 - 20 mA
Fig. 43 Wiring, analog input
24V IN
Vcc Signal
Fig. 44 Examples of external sensors
Pos. Sensor type
Differential-pressure transmitter,
1 Grundfos type DPI V.2
1/2" connection and 4-20 mA signal.
Relative-pressure transmitter.
Combined temperature and pressure sensor, Grundfos
2
type RPI T2.
1/2" connection and 0-10 V signal.
For further details, see
External Grundfos
page 59.
N
signal
Max.
250 V AC
N
2 A AC1
Signal
Min.
5 V DC
20 mA
Signal
1
2
sensors,
External control system
The analog input can be used for an external signal for
the control from a BMS system or similar control
system.
24V
Fig. 45 Example of an external signal for the control via
BMS or PLC
External setpoint function
You can use the analog input to influence the setpoint
externally. Here, a 0-10 V or 4-20 mA signal controls
the pump speed range in a linear function. The range
of control depends on the minimum speed, power and
pressure limits of the pump. See figs
(user setpoint)
H
Resulting
setpoint
Analog input
0 2
Fig. 46 External setpoint function, 0-10 V
Control
0-2 V (0-20 %) Resulting setpoint is equal to minimum.
Resulting setpoint is between minimum and
2-10 V (20-100 %)
user setpoint.
Fig. 47 Control range and setpoint
The external setpoint function operates differently,
depending on the model. For model A,B and C, the
maximum speed is often obtained at voltages lower
than 10 V as the span of control is limited.
In models newer than A,B, and C, the internal scaling
has been optimized to make the dynamic area bigger,
thus giving a better control of the pump speed when
using the external setpoint function.
The same applies if the pump is receiving a setpoint
from Building Management Systems.
BMS
PLC
46 and 47.
V
10
31
4