BEKA BA364E, Manual, Page: 10 / 60

4.1.2 Pulse input
As shown in Fig 2 the BA364G can count pulses
from a wide variety of sensors in the hazardous
area, or from the safe area as shown in Fig 3.
No Zener barrier is required in series with each input
if the intrinsically safe pulse source is located within
the same hazardous area as the BA364G Counter.
The following table shows the switching thresholds
for the various types of sensor.
For reliable
counting the pulse input must fall below the lower
threshold and rise above the upper threshold.
Input sensor
Switching thresholds
Lower Upper
Switch 100

1000

Proximity detector 1.2mA 2.1mA
Open collector
2k

10k

Magnetic pick-off 0mV 40mV peak
Voltage pulse low 1.0V 3.0V
Voltage pulse high 3.0V 10.0V
4.1.3 Switch contact input
Any mechanically activated switch contact located in
the same hazardous area as the BA364G Counter
may be directly connected to the pulse input
terminals 5 & 6 or 9 & 10 providing the switch and
associated wiring can withstand a 500V rms
insulation test to earth. Most magnetically activated
reed relays comply with these requirements. The
BA364G contains a configurable debounce circuit to
prevent contact bounce being counted.
See section 6.6 for details of debounce configuration
and the typical maximum counting frequency.
4.1.4 2-wire proximity detector input
Most certified intrinsically safe 2-wire proximity
detectors
complying with NAMUR switching
thresholds may be connected to the BA364G
Counter inputs, providing the input safety parameters
of the proximity detector are equal to or greater than
the output safety parameters of the Counter inputs
i.e.
Ui ≥ 10.5V dc
Ii ≥ 9.2mA dc
Pi ≥ 24mW
and the minimum operating voltage of the proximity
detector is less than 7.5V.
See section 6.6 for details of the typical maximum
counting frequency.
4.1.5 Open collector input
Most certified open collector sensors located in the
same hazardous area as the BA364G Counter may
be directly connected to pulse input terminals 5 & 6
and 9 & 10 providing the sensor and associated
wiring can withstand a 500V rms insulation test to
earth. The open collector device must comply with
the requirements for
simple apparatus or have input
safety parameters equal to or greater than:
Ui ≥ 10.5V dc
Ii ≥ 9.2mA dc
Pi ≥ 24mW
See section 6.6 for details of the typical maximum
counting frequency.
4.1.6 Magnetic pick-off input
CoiL
in the input configuration menu is a low level
voltage pulse input intended for use with magnetic
pick-off sensors producing an ac output. For a
CoiL
input the pulse input terminals 5 & 6 and 9 & 10 of
the BA364G Counter comply with the requirements
of
simple apparatus allowing connection to any
certified intrinsically safe magnetic pick-off within the
hazardous area having output parameters equal to
or less than:
Uo ≤ 28V dc
Io ≤ 200mA dc
Po ≤ 0.84W
The maximum permitted cable parameters will be
defined by the magnetic pick-off’s intrinsic safety
certificate less the Counters input parameters Ci and
Li which are small and can often be ignored,
See section 6.6 for details of the typical maximum
counting frequency.
4.1.7 Voltage pulse input
Two voltage pulse input ranges are selectable in the
configuration menu,
VoLt5 L
and
VoLt5 H
. When
configured for either of the voltage pulse ranges, the
pulse input terminals 5 & 6 and 9 and 10 of the
BA364G Counter comply with the requirements of
simple apparatus allowing connection to any
intrinsically safe voltage source within the hazardous
area having output parameters equal to or less than:
Uo ≤ 28V dc
Io ≤ 200mA dc
Po ≤ 0.84W
The maximum permitted cable parameters will be
defined by the voltage source intrinsic safety
certificate
less the BA364G Counter input
parameters which are small and can often be
ignored.
See section 6.6 for details of the typical maximum
counting frequency.
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