BEKA BA537E, Руководство пользователя

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9.5 Pulse output
All BA538E Rate Totalisers are supplied with an opto-
isolated pulse output. The pulse output is available as
a factory fitted option on the smaller BA537E Rate
Totaliser, but only one output option can be fitted to
this model.
The pulse output is an open collector having the
following parameters:
Ron = 60

+ 3V
Roff = 1M
I max = 10mA
The output pulse may be a duplicate of the input pulse
for re-transmission applications, or it may be derived
from the least significant digit of the total display.
When derived from the total display the output pulse
frequency may be divided and the output pulse width
defined.
The retransmitted RTx annunciator on the instrument
display shows the status of the retransmitted pulse
output.
Annunciator activation depends upon the
setting of
5ource
in the pulse output configuration
menu.
5caled:
Annunciator activated each time pulse output
open collector is
on , i.e. Ron is less than 60 Ω
+ 3V.
direct:
Annunciator continuously activated
9.5.1 System design
The Rate Totaliser pulse output is a passive circuit i.e.
not powered, but it is totally isolated from all other
Rate Totaliser circuits. The pulse output terminals P1
and P2 may be connected to another instrument
which will accept an open collector input.
Fig 14 shows how a resistor may be used to produce
a voltage pulse. The positive terminal of the pulse
output circuit P1 is connected to the BA537E or
BA538E Rate Totaliser’s positive supply terminal 1 at
the instrument. When an output pulse occurs and the
open collector 'closes', P2 is connected to P1 and a
pulse output current flows through the resistor R1.
The current flowing in the circuit is determined by
resistor R1 which should be chosen to limit the output
current to less than 10mA. For a 24V supply R1
should therefore be greater than 2,200
Ω
Fig 14 Producing a voltage pulse output
9.5.2 Configuration
All BA538E Rate Totalisers are supplied with an
opto-isolated pulse output, the pulse output is also
available as a factory fitted option on the smaller
BA537E.
Therefore the pulse output menu shown
in Fig 15 appears in the configuration menu of all
BA538E
Rate Totalisers, but only in the
configuration menu of BA537E Rate Totalisers
having an optional factory fitted pulse output.
The pulse output sub-menu enables the source of
the output pulse to be selected in the
5ourCE
sub-
function. For re-transmission applications the
output pulse may be a duplicate of the input pulse by
selecting
dirECt
in the
5ourCE
sub-function.
Alternatively, selecting
5CALEd
derives the output
pulse from incrementation of the least significant
digit of the total display. When
5caled
is selcted two
additional functions,
diVidE
and
durAtion
are
added to the sub-menu allowing the output pulse
frequency to be divided and the output pulse width
(duration) to be defined.
9.5.3 Pulse output:
PuL5E oP
The pulse output is configured in a sub-menu which
is accessed via the
pul5e op
function which is
included in all BA538E configuration menus and in
BA537E configuration menus when the optional
pulse output option is fitted.
Using the
&
or
*
push button scroll though the
configuration menu until
PuL5E oP
is displayed,
pressing
(
will then access the pulse output sub-
menu which is shown in Fig 15.
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