Non-Linear Systems
PC-40
4-Digit
Up/Down Event
Counter
INTRODUCTION
The PC-40 Digital Panel Counter is a solid-
state, 4 digit, up/down event counter or
totalizer. It is designed to provide totalizing
capability from either contact closures or
logic-level signals. The count, reset and
latch inputs are conditioned to provide high
noise immunity. It is a highly reliable
component which can be used to replace
electromechanical types.
The PC-40 is designed to operate with a
+5VDC
±
5% power supply. See Figure 1 for
a t5V power supply circuit for
operation from 120VAC.
Figure 1
. Typical Power Supply
SPECIFICATIONS
COUNT RATE:
Logic Level: * 0 to 1,000,000/sec
Contact Closure: 0 to 50/sec
*This speed is achieved by removal of internal capacitors which
normally provide filtering of contact bounce
.
INPUT SIGNAL AMPLITUDE:
Logic Level: +3.0V to +15V
Contact Closure: Ground for count
DISPLAY:
0.3" high LED, 4 Digits
OVERFLOW INDICATION:
Blinking Decimals (up only)
POWER:
+5VDC
±
5% @ 0.75W
OPERATING TEMP.:
0
°
to 50
°
C
WEIGHT:
4oz (113 g)
DECIMAL LOCATION:
Positioned by
jumper on connector to any one of 4
locations.
BCD OUTPUT:
Multiplexed, bit parallel
character serial at approximately a 600 Hz
rate.
DECIMAL POINT OUTPUT:
Multiplexed, pulse occurs on decimal point
common at the same time as the pulse for
the digit to the right of the decimal occurs.
ZERO SUPPRESSION:
Ground to
inhibit
BLANKING/DISPLAY INHIBIT:
For on or
off intensity control, connect to +5VDC
through a potentiometer (0-1K
Ω
) and switch
(if desired) maximum current is 150mA.
RESET:
Negative going to low (GND) from
logic level source on switch closure to GND.
CARRY:
At 9999 count, an output is
provided which goes positive (true). The
output goes to zero (low) at the next pulse
input to the counter. This occurs once each
10,000 pulses at the input. Designed for use
when cascading counters.
LATCH ENABLE:
(
For counts to 9999)
Open holds reading on counter at the time of
opening. Ground returns display to count at
the time of grounding (total since last reset).
OPERATING PRINCIPLES
INPUT CIRCUIT:
The input circuit contains
an amplifier-filter to permit a contact closure
to be counted as a pulse input even if
contact bounce is present. If high speed
operation (above 50 per second) is desired,
up to 1,000,000 per second, internal filter
capacitors must be removed.
Figure 2.
Simplified Block Diagram
COUNTER:
The counter is a single
integrated circuit which is capable of
counting at a 1 MHz rate to a total of 9999.
The counter provides a carry output for
cascading counter for greater range. The
counter can be reset by a logic-level signal
or a contact-closure
.
LATCH:
The latch is externally controlled to
hold and display the total count when the
latches are enabled. This count will
continue
to be displayed until the latch
enable is
removed. Release of the latch enable results
in the latches and display being updated to
the then total count on the counter. From the
latch circuits, multiplexed BCD data is
available for the four decimal digits and the
decimal point. The multiplex rate is
approximately 600 HZ. Four strobe lines are
sequentially energized to tell which decimal
digit is being output on the four BCD data
lines. The sequence begins with the most
significant digit and proceeds to the least
significant digit. This sequence is repeated
at a rate of approximately 150Hz. The data
output is the same as that presented in the
display.
DISPLAY:
The display may be used on or
off as desired. Further, it permits control of
the intensity of the display by using an
external potentiometer.
The leading zeros may be suppressed by
means of a special input; the counter will not
suppress to the decimal point selected. At
all zeros (0000), the display is blank.
INSTALLATION
Mount the PC-40 as follows:
1. Cut a hole in panel (figures 3 and 4).
2. Slide trim plate over PC-40 housing,
facing beveled edge of trim plate forward.
3. Insert PC-40 through the cutout in the
panel from the front of the panel.
4. Fit mounting clips (2) into the slots at the
sides of the meter. The foot of the clip
should face forward.
5. Thread the screws (2) into clips and
tighten the screws against the rear
surface of the panel.
Panel Cutout
w /Trim Plate
Center Line
w ithout Trim
Plate
Center Line
w /Trim Plate
Cutout For Multiple
Mounting w ithout Trim
Plate
A
2 17/32
B
31/32
C
15/16
1 3/16 min
D
3 1/8 min
3 1/8 min
E
Number of units x 15/16
Figure 3
. Mounting Data
Figure 4.
Outline Drawing
