BEKA BA337E-SS, Manual

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Input sensor
Switching thresholds
Lower Upper
Open collector
2k

10k

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

1000

Switch contacts, proximity detectors and open
collector sensors require energising which is achieved
by linking terminals 3 and 4 together as shown in
Figs 4 and 5.
4.2.3 Switch contact input
Any flowmeter with a magnetically activated switch
contact output may be directly connected to input
terminals 5 & 6 providing the flowmeter is located in
the same hazardous area as the Rate Totaliser and
the flowmeter and associated wiring can withstand a
500V rms insulation test to earth. Most magnetically
activated reed relays used in turbine flowmeters
comply with these requirements. The BA337E-SS
contain a configurable debounce circuit to prevent
contact bounce being counted. Three levels of de-
bounce protection are independently available. See
section 6.7.
4.2.4 Open collector input
Certified intrinsically safe flowmeters with an open
collector output may be directly connected to input
terminals 5 & 6 providing the flowmeter is located in
the same hazardous area as the Rate Totaliser, and
the flowmeter and associated wiring can withstand a
500V rms insulation test to earth.
The BA337E-SS contain a configurable debounce
circuit to prevent false triggering. Three levels of de-
bounce protection are independently available. See
section 6.7.
4.2.5 2-wire proximity detector input
Most certified intrinsically safe flowmeters
incorporating a NAMUR 2-wire proximity detector
may be directly connected to a BA337E-SS input,
providing the input safety parameters of the
proximity detector are equal to or greater than the
output safety parameters of the BA337E-SS input.
The (flowmeter) proximity detector input safety
parameters should be:
Ui ≥ 10.5V dc
Ii ≥ 8.2mA dc
Pi ≥ 24mW
and the minimum operating voltage of the flowmeter
(proximity detector) should be less than 7.5V. The
flowmeter must be located in the same hazardous
area as the Rate Totaliser and with the associated
wiring be able to withstand a 500V rms insulation
test to earth.
The BA337E-SS contain a configurable debounce
circuit to prevent false triggering of the instrument.
Three levels of de-bounce protection are available.
See section 6.7.
4.2.6 Magnetic pick-off input
Flowmeters incorporating a magnetic pick-off to
sense flow will have a low level voltage output
unless the flowmeter incorporates an amplifier.
CoiL
in the BA337E-SS input configuration menu is a low
level voltage pulse input intended for use with an
intrinsically safe magnetic pick-off. When a Rate
Totaliser 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 flowmeter's Co and Lo specified on it's intrinsic
safety certificate, less the Rate Totalisers pulse input
parameters Ci and Li which are small and can often
be ignored.
The flowmeter must be located within the same
hazardous area as the BA337E-SS and together
with the associated wiring be able to withstand a
500V rms insulation test to earth.
The BA337E-SS contain a configurable debounce
circuit to prevent false triggering of the instrument.
See section 6.7.
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