BEKA BA374NC, Manual, Page: 27 / 27

12. BACKLIGHT
The BA374NC can be supplied with LED
backlighting to improve display contrast when the
transmitter is installed in a poorly illuminated area.
The backlight is electrically segregated from the
measuring circuit and has been certified as a
separate EEx nL Group II, Category 3G circuit.
The Type n input safety parameters are:
Ui 30V dc
Ii 100mA
Pi 1.3W
This allows the backlight to be powered from a
safe area 18 to 30V dc supply as shown in Fig 13.
Providing the supply voltage in normal operation is
less than 30V dc, the backlight safety components
will ensure that the maximum input current and
power are within the safety limits.
Fig 13 Backlight power supply
Reduced the supply voltage below 18V, or by
adding a current limiting resistor in series with the
supply, will reduce the display brilliance.
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