Start/Stop Of Pump; Other Connections; Signal Cables; Pump Control - Grundfos CRE Montage- Und Betriebsanleitung

2.1.7 Start/stop of pump

The number of starts and stops via the mains voltage must not
exceed 4 times per hour.
If a higher number of starts and stops is desired, the input for ex-
ternal start/stop must be used when starting/stopping the pump.
When the pump is switched on via the mains, the pump will start
after approx. 5 seconds.

2.2 Other connections

The connection terminals of external potential-free contacts for
start/stop, external setpoint signal and relay signal are shown in
fig. 3.
Note: If no external on/off switch is connected, short-circuit termi-
nals 2 and 3 using a short wire.
Note: As a precaution, the wires to be connected to the following
connection groups must be separated from each other by rein-
forced insulation in their entire lengths:
1. Inputs (external start/stop and setpoint signal, terminals
2 to 6).
All inputs (group 1) are internally separated from the mains-
conducting parts by reinforced insulation and galvanically
separated from other circuits.
All control terminals are supplied by protective extra-low volt-
age (PELV), thus ensuring protection against electric shock.
2. Output (signal relay, terminals NC, NO, C).
The output (group 2) is galvanically separated from other cir-
cuits. Therefore, the supply voltage or protective extra-low
voltage can be connected to the output as desired.
3. Supply voltage (terminals L and N).
A galvanically safe separation must fulfil the requirements for re-
inforced insulation including creepage distances and clearances
specified in EN 50 178.
Fig. 3
GND
+10 VDC
Setpoint input
GND
Start/stop
Signal relay
Mains connection

2.3 Signal cables

• Use screened cables having a cross-sectional area of min.
0.5 mm² and max. 1.5 mm² for external on/off switch and set-
point signal.
• The screens of the cables must be connected to frame at both
ends with good frame connection. They must be as close as
possible to the terminals, fig. 4.
Fig. 4
• Screws for frame connections must always be tightened
whether a cable is fitted or not.
• The wires in the pump terminal box must be as short as possi-
ble.

3. Pump control

The pump can be connected to external signals for remote-con-
trol of pump performance.

3.1 Pump speed control

The pump speed can be set via the setpoint input, terminal 4.
It is possible to use either a 0-10 V signal or a potentiometer.
Fig. 5
Speed
Setpoint
Potentiometer
The pump speed can set within the range from 24% to 100%.

3.2 Start/stop input

The pump can be started and stopped via an external potential-
free contact connected to terminals 2 and 3.
Functional diagram: Start/stop input:
Start/stop (terminals 2 and 3)
H
H
GND
+10 VDC
Setpoint input
Normal duty
Q
Stop
Q
5