Flowserve NRS 1-51 - Manual (Page 14)

4
Electrical Connection
– continued –
Tools
n
Screwdriver for slotted screws, size 3.5 x 00 mm, completely insulated according to VDE 0680-.
Danger
n
For the supply of the level switch NRS -5 with 4 V DC use a safety extra-low
voltage (SELV) power supply unit that must be electrically isolated from dangerous
contact voltages and must meet at least the requirements on double or reinforced iso-
lation acc. to DIN EN 5078 or DIN EN 600- or DIN EN 60730- or DIN EN 60950
(safe electrical isolation).
n
Any item of equipment that you want to connect to terminals 6, 7 (standby input )
must be certified to have at least double or reinforced isolation according to DIN
EN 5078 or DIN EN 600- or DIN EN 60730- or DIN EN 60950 (safe electrical
isolation) between the standby inputs and the live parts of the installation that are not
supplied with safety extra-low voltage (SELV).
Attention
n
Fuse the level switch NRS -5 with an external semi-delay fuse 0.5 A.
n
Connect screens of electrode wires only to terminal 5.
n
To protect the switching contacts fuse the safety circuit with a slow-blow fuse  A or 
A (for 7 hrs. operation acc. to TRD 604).
n
When switching off inductive loads, voltage spikes are produced that may impair the
operation of control and measuring systems. Connected inductive loads must be pro-
vided with suppressors such as RC combinations as specified by the manufacturer.
n
When used as high water level alarm according to TRD, EN 95 / EN 953 connect
terminals 4 and 6 by fitting a wire link.
n
Install connecting lines to level electrodes and logic unit separated from power cables.
n
Do not use unused terminals as support point terminals.
A signal output for the connection of external signalling equipment is allocated to the monitoring
channel in the level switch, max. load 00 mA. For connecting the level switch with the logic unit use
a control cable, e.g.  x 0.5 mm  . In the event of an alarm or error message the signal output
(terminals 0, ) closes instantaneously.
Connection for signal output