IM-P402-129
EMM Issue 7
18
5.3 Signal wiring notes
An earth current loop is created if a wire or screen is connected between two earth points
that are at different potential (voltage). If the wiring diagram is followed correctly, the screen
will only be connected to the earth at one end.
The earth terminal is a functional earth rather than a protective earth.
A protective earth provides protection from electric shock under a single fault condition. This
product has double insulation and therefore does not require a protective earth. A functional
earth is used in order for the product to operate. In this application, the earth is used as a
sink or drain for any electrical interference. The earth terminal must be connected to a local
earth in order to conform to the EMC directive.
Warning:
The earth lead is internally connected to the probe body and therefore earthed via the NPT
or BSP thread. Do not connect this earth pin to other earths.
5.4 Probe wiring
The maximum cable length for all transducers is 100 m (328 ft).
Signal circuit
(View from the top)
Fr
ont
50 51 52 53 54 55 56
1
2
3
LP31
Connect to a clean
local earth in the panel
Fig. 7 Signal circuit LP31
Alarm
1
Pump
tip
HI
Pump
tip
LO
Alarm
2
Com Screen E
Bac
k
Summary of Contents for LC1350
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