9
3.8 Other connections
The connection terminals of external potential-free contacts for
start/stop and digital function, external setpoint signal, sensor
signal, GENIbus and relay signal are shown in fig. 11.
1.
Inputs
(external start/stop, digital function, setpoint and sen-
sor signals, terminals 1-8, and bus connection, terminals
A, Y, B).
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
voltage (PELV), thus ensuring protection against electric
shock.
2.
Output
(relay signal, terminals NC, NO, C).
The output (group 2) is galvanically separated from other
circuits. A maximum supply voltage of 250 V or protective
extra-low voltage can be connected to the output as desired.
A galvanically safe separation must fulfil the requirements for
reinforced insulation including creepage distances and
clearances specified in EN 60 335.
Fig. 11
Connection terminals
3.9 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, digital
input, setpoint and sensor signals.
• 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. 12.
Fig. 12
Stripped cable with screen and wire connection
• 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
possible.
3.10 Bus connection cable
3.10.1 New installations
For the bus connection a screened 3-core cable having a cross-
sectional area of min. 0.5 mm² and max. 1.5 mm² must be used.
• If the pump is connected to a unit with a cable clamp which is
identical to the one on the pump, the screen must be
connected to this cable clamp.
• If the unit has no cable clamp as shown in fig. 13, the screen is
left unconnected at this end.
Fig. 13
Connection with screened 3-core cable
3.10.2 Replacing an existing pump
• If a screened 2-core cable is used in the existing installation, it
must be connected as shown in fig. 14.
Fig. 14
Connection with screened 2-core cable
• If a screened 3-core cable is used in the existing installation,
follow the instructions in section
Note
If no external on/off switch is connected, short-
circuit terminals 2 and 3 using a short wire.
As a precaution, the wires to be connected to the
following connection groups must be separated
from each other by reinforced insulation in their
entire lengths:
T
M
02
19
52
26
01
G
rou
p 2
G
ro
up 1
8: +24 V
7: Sensor input
6: GND (frame)
5: +5 V
4: Setpoint input
3: GND (frame)
2: Start/stop
1: Digital input
A: RS-485A
Y: Screen
B: RS-485B
Signal relay
NC
NO
C
T
M
02
1
3
25
09
01
TM
02 88
41 090
4
T
M
02
88
42
09
04
A
Y
B
A
Y
B
1
2
3
1
2
3
Pump
A
Y
B
A
Y
B
1
2
1
2
Pump
Grundfos.bk Page 9 Tuesday, April 17, 2007 8:54 AM
