BEKA BA568E, Manual

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6. Pulse output
The BA568E Counter has an opto-isolated solid
state pulse output. The output is an open collector
having the following electrical parameters:
Ron = 60

+ 3V
Roff = 1M
Imax = 10mA
The output pulse may be a duplicate of Input A or
Input b for re-transmission applications, or it may be
derived from 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
6.1 System design
The BA568E Counter pulse output is a passive
circuit i.e. not powered, but it is totally isolated from
all other Counter circuits. Terminals P1 and P2 may
be directly connected to another instrument that can
accept an open collector input. Polarity should be
observed.
Fig 9 shows how a voltage pulse can be generated.
The positive terminal of the pulse output circuit P1 is
connected to the Counter’s positive supply terminal
1. When an output pulse occurs and the open
collector 'closes', P2 is connected to P1 and a pulse
current flows through the diode return barrier to
resistor R1 in the safe area. The current flowing in
the circuit is defined by resistor R1 which should be
chosen to limit the pulse current to less than 10mA.
For a 24V supply R1 should be greater than 2,200
Ω
Fig 9 Generating voltage pulse in safe area
using Zener barriers.
6.2 Configuration
The pulse output is configured via a
PuL5E oP
sub-menu located between the
LoC CLr
and the
Clr Gtot
functions in the configuration menu as
shown in Fig 10.
This sub-menu allows the source of the output pulse
to be selected. For re-transmission applications the
output pulse may be a synchronous duplicate of the
pulse at Input A or at Input b by selecting
dirECt A
or
dirECt b
in the
5ourCE
sub-function.
Selecting
5CALEd
derives the output pulse from the
total display and introduces two additional functions,
diVidE
and
durAtion
to the sub-menu allowing the
output pulse frequency to be divided and the output
pulse width (duration) to be defined.
If the
diVidE
and
durAtion
functions are configured
such that the output pulse frequency with the
specified pulse width can not be output in real time,
the number of pulses will be stored and transmitted
at the maximum possible speed.
When the total display is reset to zero or the power
supply to the BA568E Counter is disconnected or
turned off, any stored pulses will not be retained
.
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