BEKA BA578C, Руководство пользователя

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ACCESSORIES
9. IDENTIFICATION
9.1 Scale card
The BA578C has a window on the right hand side
of the display to hold a card showing the units of
measurement e.g.
o
C,
o
F, kg. The transmitter
can be supplied with a printed scale card showing
any units specified at time of ordering. If a printed
scale card is not requested a blank card will be
fitted.
Scale cards can easily be marked on site as
follows:
a. Un-plug the rear terminal block(s),
disconnect the input wires and remove the
rear panel which is secured by four corner
screws.
b. Withdraw the transmitter assembly from
the enclosure.
c. Gently pull and then slide the blank scale
card towards the display window until it is
free. Mark the card with the required
legend and replace it in the slot.
d. Insert the transmitter assembly into the
enclosure, fit the rear panel and terminal
blocks and reconnect the input wires.
9.2 Tag strip
The BA578C can be supplied with a thermally
printed tag strip on the rear panel with any legend
containing up to 35 alphanumeric characters. This
strip is not visible from the front of the instrument
after installation.
10. ALARMS
The optional alarms provide two solid state single
pole 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 transmitter is not powered. When an
alarm is activated the indicator display alternates
between the measured value and an alarm
identification.
WARNING
These alarm outputs should not be used
for critical safety applications such as a
shut-down system.
Fig 8 Alarm outputs
Programmable functions for each alarm include
adjustable hysteresis, alarm delay and alarm
accept.
10.1.1 Solid state output
Each alarm has a galvanically isolated single pole
solid state switch output as shown in Fig 11. The
output is polarised and current will only flow in one
direction
Fig 9 Equivalent circuit of each alarm output
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