Grundfos MAGNA3 Manual page 30

4
Relay outputs
The pump has two signal relays with a potential-free
changeover contact for external fault indication.
You can set the function of the signal relay to Alarm,
Ready or Operation on the pump operating panel or
with Grundfos GO.
Factory settings of relays:
Relay
1
2
Note: You can configure both relays to "ready, alarm or
operating".
M M
S/S
A
Fig. 40 Relay output in the control box
Contact symbol
NC
NO
C
The functions of the signal relays are as shown in the
table below:
Signal relay Alarm signal
Not activated:
• The power supply has been switched off.
1 2 3
• The pump has not registered a fault.
NC NO C
1 2 3
NC NO C
Activated:
• The pump has registered a fault.
1 2 3
NC NO C
Signal relay Ready signal
Not activated:
• The pump has registered a fault and is unable to
1 2 3
run.
NC NO C
1 2 3
NC NO C
Activated:
• The pump has been set to stop, but is ready to run.
• The pump is running.
1 2 3
NC NO C
Signal relay Operating signal
Not activated:
• The pump is not running.
1 2 3
1 NC NO C 2 3
NC NO C
Activated:
• The pump is running.
1 2 3
NC NO C
30
Function
Operation signal
Alarm signal
NC N0 C
Function
Normally closed
Normally open
Common
Analog input for an external sensor
To optimize pump performance, you can use the
analog input for the connection of an external sensor in
the following cases:
Function/control mode Sensor type
Heat energy monitor
Temperature sensor
Constant temperature
Constant pressure Differential-pressure transmitter
When using an external differential-pressure sensor to
control the flow in the system, you obtain the externally
set pressure, which results in the following benefits:
• minimizes operating costs
• prevents valve noise
• ensures comfort (adequate pressure).
Fig. 41 External differential-pressure sensor
MAGNA3