3. SYSTEM DESIGN
Fig 2 illustrates the basic circuit that is used for all
BA568E Counter installations. For simplicity,
connections for the pulse output and the optional
alarms and 4/20mA output are shown separately in
sections 6 and 9 of this manual.
Fig 2 BA568E connections
When designing a system it is important to
remember that terminals 2, 6, 10 and RS2 are
interconnected within the BA568E See Fig 1.
3.1 Power supply
The BA568E Counter requires a 10 to 30V dc supply
between terminal 1 & 2 and consumes:
10mA
plus 16mA for optional backlight
plus 6mA when terminals 3 & 4 are linked
plus 6mA when terminals 7 & 8 are linked
______
38mA
3.2 Pulse input
As shown in Fig 2 the BA568E can count pulses
from a wide variety of sensors.
The following table shows the switching thresholds
for the various types of sensor. For reliable
counting the pulse input must fall below the lower
threshold and rise above the upper threshold.
Input sensor
Switching thresholds
Lower Upper
Switch 1001000
Proximity detector 1.2mA 2.1mA
Open collector 2k10k
Magnetic pick-off 0 40mV peak
Voltage pulse low 1.0V 3.0V
Voltage pulse high 3.0V 10.0V
3.2.1 Switch contact input
Any switch contact may be directly connected to the
pulse input terminals 5 & 6 and 9 & 10. Each input
of the BA568E contains a configurable debounce
circuit to prevent contact bounce being counted.
See section 5.6 including details of the maximum
counting frequency.
3.2.2 2-wire proximity detector input
Most NAMUR 2-wire proximity detector may be
connected directly to the BA568E pulse inputs,
providing the minimum operating voltage of the
proximity detector is less than 7.5V. Each input of
the BA568E contains a configurable debounce
circuit to prevent contact bounce being counted.
See section 5.6 including details of the maximum
counting frequency.
3.2.3 Open collector input
Sensors with an open collector output may be
directly connected to Counter input terminals 5 & 6
and 9 & 10. Polarity of the sensor output should be
observed. Each input of the BA568E contains a
configurable debounce circuit to prevent contact
bounce being counted. See section 5.6 including
details of the maximum counting frequency.
3.2.4 Magnetic pick-off input
Sensors incorporating a magnetic pick-off will have a
low level voltage output unless the sensor
incorporates an amplifier. CoiL in the BA568E input
configuration menu is a low level voltage pulse input
intended for use with a magnetic pick-off. Each
input of the BA568E contains a configurable
debounce circuit to prevent contact bounce being
counted. See section 5.6 including details of the
maximum counting frequency.
3.2.5 Voltage pulse input
Two voltage pulse input ranges are selectable in the
BA568E Counter configuration menu, VoLt5 L and
VoLt5 H as shown in section 3.2. Each input of the
BA568E contains a configurable debounce circuit to
prevent contact bounce being counted. See section
5.6 including details of the maximum counting
frequency.
3.3 Remote reset
The Counter's total display may be remotely reset
by connecting terminals RS1 and RS2 together for
more than one second. Permanent interconnection
inhibits counting.
Note: The BA568E may also be configured to
reset the total display by operating the &
and *push buttons simultaneously for
more than two seconds in the counting
mode. See 5.24
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