BEKA BA377E-SS, Manual

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3.1.5 2-wire proximity detector input
Most intrinsically safe NAMUR 2-wire proximity
detectors may be connected to the BA377E-SS
sensor input, providing the input safety parameters
of the proximity detector are equal to or greater than
the output safety parameters of a BA377E-SS input.
i.e.
Ui ≥ 10.5V dc
Ii ≥ 8.2mA dc
Pi ≥ 25mW
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
BA377E-SS.
The BA377E-SS contains a configurable debounce
circuit to prevent false triggering of the instrument.
Three levels of debounce protection are available.
See section 6.5.6.
3.1.6 Magnetic pick-off input
CoiL
in the input configuration menu is a low level
voltage input intended for use with an intrinsically
safe magnetic pick-off sensor which is not suitable
for controlling a BA377E-SS.
3.1.7 Voltage input
Two voltage input ranges are selectable in the
BA377E-SS Timer configuration menu,
VoLt5 L
and
VoLt5 H
. When configured for either of the voltage
ranges and terminals 3 and 4 are not linked, the
input terminals 5 and 6 comply with the requirements
for
simple apparatus . This allows the input to be
connected to any certified intrinsically safe voltage
source located within the same hazardous area as
the BA377E-SS having output parameters equal to
or less than:
Uo ≤ 28V dc
Io ≤ 200mA dc
Po ≤ 0.84W
The BA377E-SS Timer may therefore be directly
connected to and controlled by most certified
intrinsically safe high level voltage signals.
The maximum permitted cable parameters will be
defined by the intrinsic safety certification of the
voltage source less the BA377E-SS input
parameters which are small and can often be
ignored.
The BA377E-SS contains a configurable debounce
circuit to prevent false triggering of the instrument.
Three levels of debounce protection are available.
See section 6.5.6.
3.1.8 Remote reset
Connecting the external reset terminals RS1 and
RS2 together will reset the BA377E-SS when
configured as a Timer and synchronise the displayed
time when configured as a Clock. Remote resetting
may be accomplished by any mechanically operated
switch located in the same hazardous area as the
instrument providing the switch and the associated
wiring can withstand a 500V rms insulation test to
earth. No Zener barrier is required.
A BA377E-SS may also be remotely reset from the
safe area. Any switch may be used but a Zener
barrier is required to transfer the contact closure into
the hazardous area which may be combined with the
supply barrier so that only one package is required.
A diode return barrier is not suitable for this
application. Fig 1 illustrates how a BA377E-SS may
be reset from both the safe and the hazardous area.
Note: When used as a Timer the BA377E-SS may
also be reset from the display mode by operating the
&
and
*
push buttons simultaneously for more
than two seconds. See 6.5.19