Grundfos MAGNA3 25-80 Installation And Operating Instructions Manual page 31

Factory settings of relays:
Relay
1
2
Relay output in twin-head pumps
The relay output for both the "Alarm", "Ready" and "Operation"
functions operates independently on each pump head. If, for
example, a fault occurs in one of the pumps, its respective relay
is triggered.
7.9.3 Digital inputs
The pump has a digital input for external control of start-stop or
forced maximum or minimum curve. See section
diagrams.
If no external on-off switch is connected, the jumper between
terminals start-stop (S/S) and frame ( ) must be maintained. This
connection is the factory setting.
M
M
A I
Start-stop
Fig. 46 Digital input
Contact symbol
M
A
M
I
S/S
Function
Operating signal
Alarm signal
3.9 Wiring
S/S
On-off timer
Function
Maximum curve
100 % speed
Minimum curve
Start-stop
Frame connection
External start-stop
You can start and stop the pump via the digital input.
Start-stop
S/S
H
Q
H
S/S
Q
Externally forced maximum or minimum curve
You can force the pump to operate on the maximum or minimum
curve via the digital input.
Maximum curve
M H
A
M
H
A
Minimum curve
H
M
I
M
H
I
Select the function of the digital input on the pump operating
panel or with Grundfos GO.
Digital input on twin-head pumps
The Start/Stop input operates on system level, meaning that if the
master pump head receives a stop signal, the system stops.
As a main rule, the digital input is only effective on the master,
which is why it is important to know which pump is assigned as
master, see fig. 47.
XXXXXXXXXXXXXXXXXXXXXXXX
P/N: XXXXXXXX
IP XXX TF XXX
S/N: XXXXXXXX
PC: XXXX
Model: X
Made in Germany y
Grundfos Holding A/S, DK - 8850 Bjerringbro, Denmark enmark
Fig. 47 Identifying the master pump head on the nameplate
For redundancy purposes, the digital input can be used
concurrently on the slave pump head. However, as long as the
master is powered up, the input on the slave will be ignored. In
the event of power loss on the master, the digital input of the
slave will take over. When the master pump head is back on, the
master takes over and controls the system.
Normal duty
Factory setting with jumper
between start-stop and .
Stop
Normal duty
Q
Maximum curve
Q
Normal duty
Q
Minimum curve
Q
I [A] P [W] MPa
1 1
XXXX
XXXX XX
ark rk rk k
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