BEKA BA314E, Manual

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4.2.5 2-wire proximity detector input
Most certified intrinsically safe NAMUR 2-wire
proximity detectors may be directly connected to a
BA314G input, providing the input safety parameters
of the proximity detector are equal to or greater than
the output safety parameters of a BA314G input:
Ui ≥ 10.5V dc
Ii ≥ 8.2mA dc
Pi ≥ 24mW
and the minimum operating voltage of the proximity
detector is less than 7.5V. The proximity detector
must be located in the same hazardous area as the
Tachometer and the associated wiring must be able to
withstand a 500V rms insulation test to earth.
The BA314G contain a configurable debounce circuit
to prevent false triggering of the instrument. Three
levels of de-bounce protection are available.
See section 6.6.
4.2.6 Magnetic pick-off input
CoiL
in the BA314G input configuration menu is a low
level voltage pulse input intended for use with an
intrinsically safe magnetic pick-off. When a
Tachometer input is configured for
CoiL
and terminals
3 & 4 are not linked, input terminals 5 & 6 comply with
the requirements for
simple apparatus allowing
connection to any certified intrinsically safe magnetic
sensor having output parameters equal to or less
than:
Uo ≤ 28V dc
Io ≤ 200mA dc
Po ≤ 0.84W
The maximum permitted cable parameters will be be
the sensor's Co and Lo specified on it's intrinsic safety
certificate, less the Tachometers pulse input
parameters Ci and Li which are small and can often
be ignored.
The sensor must be located within the same
hazardous area as the BA314G and with the
associated wiring must be able to withstand a 500V
rms insulation test to earth.
The BA314G Tachometer contains a configurable
debounce circuit to prevent false triggering. Three
levels of debounce protection are available. See
section 6.6.
4.2.7 Voltage pulse input
Two voltage pulse input ranges are independently
selectable in the BA314G Tachometer configuration
menu,
VoLt5 L
and
VoLt5 H
. When configured for
either of the voltage pulse ranges, and terminals 3 &
4 are not linked, the input terminals 5 & 6 comply
with the requirements for
simple apparatus . This
allows the pulse input to be connected to any
certified intrinsically safe sensor with a voltage
output located within the same hazardous area as
the Tachometer providing it has output parameters
equal to or less than:
Uo ≤ 28V dc
Io ≤ 200mA dc
Po ≤ 0.84W
The BA314G Tachometers may therefore be directly
connected to most certified intrinsically safe sensors
with a high level voltage output.
The maximum permitted cable parameters will be
defined by the sensor's intrinsic safety Co and Lo
less the Tachometer's pulse input parameters Ci and
Li which are small and can often be ignored.
The BA314G contain a configurable debounce circuit
to prevent false triggering of the instrument. Three
levels of de-bounce protection are available.
See section 6.6.
4.2.8 Remote reset
The Tachometer's run-time display may be remotely
reset to zero by connecting terminals RS1 and RS2
together for more than one second. Permanent
interconnection inhibits the run-time clock. Remote
resetting may be accomplished by any mechanically
operated switch located in the same hazardous area
as the Tachometer providing the switch and the
associated wiring can withstand a 500V rms
insulation test to earth. No galvanic isolator is
required.
A BA314G may also be remotely reset from the safe
area. Any switch may be used but a galvanic
isolator is required to transfer the contact closure
into the hazardous area. Fig 4 illustrates how a
BA314G may be reset from both the safe and the
hazardous area.
Note: The BA314G Tachometer may be
configured to reset the total display to zero
by operating the
&
and
*
push buttons
simultaneously for more than two seconds
in the totalising mode i.e. when the
instrument is displaying flow. See 6.15
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