BEKA BA568E, Manual

Page: 27 / 33

9. ACCESSORIES
9.1 Scale card
The BA568E Counter has a window on the right
hand side of the display through which a scale card
showing the units of measurement such as metres is
visible. New Counters are fitted with a scale card
showing the units of measurement specified when
the instrument was ordered, if the units are not
specified a blank scale card will be fitted. A pack of
scale cards pre-printed with common units of
measurement is available as an accessory. These
can easily be fitted on-site to the Counter without
opening the instrument enclosure or removing it from
the panel, See section 4.4 of this instruction
manual.
Custom scale cards for applications requiring less
common units of measurement are also available.
9.2 Tag information
New Counters can be supplied with a tag number or
application information thermally printed onto the
rear panel adjacent to the terminals. This
information is not visible from the front of the
instrument after installation.
9.3 Alarms
The BA568E Counter can be supplied with factory
fitted dual alarms. Each may be independently
configured as a rate display or total display, high or
low alarm. with a normally open, or a normally
closed solid state output.
Configurable functions for each alarm include
adjustable setpoint, alarm delay time and alarm
silence time. Hysteresis may be applied to rate
alarms.
CAUTION
These alarm outputs should not be used
for critical safety applications such as a
shut down system.
When the BA568E power supply is turned off or
disconnected, alarm outputs will open irrespective of
whether normally open or normally closed outputs
have been selected. When designing a system an
open output should therefore be chosen for the
alarm condition.
Alarm annunciators on the instrument display
indicate the status of each alarm. If an alarm delay
or silence time has been selected the annunciator
will flash during the delay or silence period.
The BA568E internal counters are up-dated and
compared with the alarm setpoint twice per second,
irrespective of the display update time selected.
This may result in an alarm being delayed for up to
half a second after the rate or total has exceeded the
setpoint.
9.3.1 Solid state output
Each alarm has a galvanically isolated single pole
solid state switch output as shown in Fig 11. The
outputs are polarised and current will only flow in
one direction. Terminals A1 and A3 should be
connected to the positive side of the supply.
Ron = less than 5

+ 0.7V
Roff = greater than 1M

Note: Because of the series protection diode some
test meters may not detect a closed alarm
output
Fig 11 Equivalent circuit of each alarm output
The solid state output of each alarm may be used to
switch any circuit with parameters equal or less than:
V max = 30V
I max = 200mA
27