BEKA BA377NE, Руководство пользователя

Страница: 9 / 47

9
Providing the BA377NE Timer or Clock is correctly
installed in an Ex n panel enclosure located in
Zone 2, the input terminals may be connected to a
certified sensor located in Zone 1 as shown in Fig 4.
The sensor should have Ex e or Ex d certification
permitting installation in Zone 1.
Intrinsically safe
Ex i certified sensors should not be used.
Fig 4 Connection to an Ex d or Ex e sensor in
Zone 1.
3.2.1 Input switching threshold
For reliable totalisation the Timer or Clock pulse
input must fall below the lower threshold and rise
above the upper thresholds shown in the following
t
able.
Input transducer
Switching thresholds
Lower Upper
Open collector 2k Ω 10k Ω
Voltage pulse
low
1.0V 3.0V
Voltage pulse
high
3.0V 10.0V
Magnetic pick-off 0mV 40mV peak
Proximity
detector
1.2mA 2.1mA
Switch 100 Ω 1000 Ω
Switch contact, proximity detector and open
collector sensors require energising which is
achieved by linking BA377NE terminals 3 and 4.
3.2.2 Switch contact input
Any mechanically or magnetically activated switch
contact located in Zone 2 or in the safe area may be
directly connected to the BA377NE pulse input
terminals 5 and 6, providing the sensor and
associated wiring can withstand a 500V rms
insulation test to earth. Most magnetically activated
reed relays comply with these requirements.
The BA377NE contain a configurable debounce
circuit to prevent false triggering. See section 6.5.6.
3.2.3 Open collector input
Open collector sensors located in Zone 2 or in the
safe area may be directly connected to input
terminals 5 & 6 providing the sensor and associated
wiring can withstand a 500V rms insulation test to
earth.
The BA377NE contain a configurable debounce
circuit to prevent false triggering. See section 6.5.6.
3.2.4 2-wire proximity detector input
Most Zone 2 certified NAMUR 2-wire proximity
detectors may be directly connected to a BA377NE
input terminals 5 & 6 providing minimum operating
voltage is greater than 7.5V. The sensor and the
associated wiring should be able to withstand a
500V rms insulation test to earth.
The BA377NE contain a configurable debounce
circuit to prevent false triggering. See section 6.5.6.
3.2.5 Magnetic pick-off input
Magnetic pick-offs will usually have a low level ac
voltage output which a BA377NE Timer or Clock can
sense when configured for a
CoiL
input. The Timer
or Clock input terminals 5 and 6 may be connected
to any Zone 2 certified magnetic pick-off sensor
providing the output in normal operation is less than
30V which is the Ui of the BA377NE. The sensor
and associated wiring should be able to withstand a
500V rms insulation test to earth.
The BA377NE contain a configurable debounce
circuit to prevent false triggering. See section 6.5.6.
3.2.6 Voltage pulse input
Two voltage pulse input ranges are selectable in the
BA377NE Timer or Clock configuration menu,
VoLt5
L
and
VoLt5 H
. The Timer or Clock input terminals
5 and 6 may be connected to any Zone 2 certified
voltage pulse, providing the output in normal
operation is equal to or less than 30V and the
sensor and associated wiring are able to withstand a
500V rms insulation test to earth.
The BA377NE contain a configurable debounce
circuit to prevent false triggering. See section 6.5.6.