BEKA BA524D, Manual

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8. ACCESSORIES
8.1 Units of measurement and instrument
identification
All BA524D indicators are fitted with a blank label
around the liquid crystal display. This label can be
supplied printed with any units of measurement
and tag information specified at the time of
ordering. Alternatively the information may be
added on-site via an embossed strip, dry transfer
or a permanent marker.
To gain access to the display label remove the
terminal cover by unscrewing the two 'A' screws
which will reveal two concealed 'D' screws. If the
instrument is fitted with external push-buttons also
unscrew the two 'C' screws securing the buttons
and un-plug the five way connector. Finally
unscrew the four 'D' screws and carefully lift off the
front of the instrument - see Fig 4. Add the
required legend to the display label, or replace with
a new pre-printed label which is available from
BEKA associates
The BA524D can also be supplied with a blank or
custom engraved stainless steel plate secured by
two screws to the side of the instrument enclosure.
This plate can accommodate:
1 row of 9 alphanumeric characters 10mm high
or 1 row of 11 alphanumeric characters 7mm high
or 2 rows of 18 alphanumeric characters 5mm high.
8.2 Alarms
The BA524D can be supplied with two solid state
single pole alarm outputs which may be
independently programmed as high or low alarms
with normally open or normally closed outputs. Fig
8 illustrates the conditions available and shows
which are fail safe, i.e. output is in the alarm
condition (open) when the 4/20mA input current is
zero.
WARNING
These alarm outputs should not be used
for critical safety applications such as a
shut down system.
When an alarm is activated, the BA524D display
alternates between the measured value and an
alarm identification.
Fig 8 Alarm outputs
Programmable functions for each alarm include
adjustable setpoint, hysteresis, alarm delay and
alarm accept.
8.2.1 Solid state output
Each alarm has a galvanically isolated single pole
solid state switch output as shown in Fig 9. The
outputs are polarised and current will only flow in
one direction. Terminals 8 and 10 should be
connected to the positive side of the supply.
Ron = 5ohms + 0.6V
Roff = greater than 180k
Note: Because of the series protection diode
some test meters may not detect a closed alarm
output.
Fig 9 Equivalent circuit of each alarm output
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