BEKA BA364E, Manual

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4.1.8 Remote reset
The BA364G Counter total display may be remotely
reset to zero by connecting terminals RS1 & RS2
together for more than one second. Permanent
interconnection inhibits counting. Remote resetting
may be accomplished by any mechanically operated
switch located in the same hazardous area as the
Counter providing it and the associated wiring can
withstand a 500V rms insulation test to earth. No
Zener barrier is required.
A BA364G 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 2 illustrates how the BA364G total
display may be reset from both the safe and the
hazardous area.
Note: The BA364G can be configured to reset the
total display to zero when the
&
and
*
push
buttons are operated simultaneously for more than
three seconds - see 6.24.
4.2 Use with Galvanic Isolators
Galvanic isolators are probably the simplest
intrinsically safe interface to install as they provide
isolation and do not require a high integrity earth
connection.
Any certified galvanic isolator with output parameters
less than the input parameters of the BA364G having
the correct function may be used.
Fig 4 BA364G protected by galvanic isolators.
Fig 4 illustrates the basic circuit that is used for all
BA364G Counter installations protected by galvanic
isolators. For simplicity, connections for the pulse
output, optional alarms and 4/20mA output are
shown separately in sections 7 and 10 of this
manual.
Alternatively the pulse source may be located in the
safe area. Fig 5 shows how an additional galvanic
isolator is used to transfer the signal to the BA364G
Counter in the hazardous area, although it may be
difficult to find isolators for some sensors.
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