Important Instructions For Connecting The Device - Grundfos Conex DIS-C Installation And Operating Instructions Manual

9.4 Important instructions for connecting
the device
As is common in microprocessor-controlled devices,
certain precautions must be taken during installation
and wiring. In addition to the general guidelines, the
following is of particular importance:
• Input wires and control wires must be laid
separately from one another and from power
supply cables.
• Analog output wires must be screened.
The screen can be connected to the device.
• Relays and protective spools must remain free of
interference.
• If inductive loads are connected, they must either
be screened, or the relay contact must be
protected on the clamping strip of the
®
Conex DIS-C by an RC protective circuit, in
accordance with the following table and the
switching diagrams.
9.4.1 Power supply
Warning
Before connecting the device, switch off
the power supply!
• The device is connected to the power supply at
the clamps (L), (N) and (PE).
• Check the correct supply voltage on the
nameplate.
Connection of an incorrect supply voltage
Caution
may destroy the device!
9.4.2 Connecting the conductivity measuring cell
For connecting the conductivity cell to the
®
Conex DIS-C, only use the prescribed
cable. This cable must not be used in the
same cable channel as power supply
Caution
cables!
Protect cable connections and plugs
against corrosion and moisture!
9.4.3 Relay outputs
If inductive loads (including relay and protective spools)
are connected, they must be screened. If this is not
possible, the relay contact must be protected using a
protection circuit in accordance with the table below.
For AC current
Current up to Capacitor C
60 mA 10 nF, 260 V
70 mA 47 nF, 260 V
150 mA 100 nF, 260 V
1.0 A 220 nF, 260 V
R = 47 to 390 Ω
C = 10 nF to 220 nF / 260 V
e.g. Siemens MKC B 81 921
Values can be found in the
above table.
Protection circuit with AC current
Fig. 10
For DC voltage
The relay or protective spool must be screened with
a suppressor diode.
+
-
Protection circuit with DC voltage
Fig. 11
Warning
If floating relay outputs are used, they
must be supplied with a backup fuse!
9.4.4 Current outputs
When connecting the electrical outputs, be
Caution
aware of the polarity and the maximum
load (500 Ω)!
Use a screened cable for connecting the
Caution electrical outputs. The screen must be
connected to PE with one end.
Resistor R
390 Ω, 2 W
22 Ω, 2 W
47 Ω, 2 W
47 Ω, 2 W
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