AMETEK 7100 Leak Detect Stik - Manual (Page 13)

11
Figure 7: Typical Console Circuitry
-
+
Comparator
+1 VDC
Reference Always use the
leading edge
Counter
Gating Circuit
High Speed
Counters
High Speed Clock
(20-110 mH)
Intrinsic Safety Barrier
Return signals are coupled through the VCC Pin and the
150 Ohm barrier resistor and coupling capacitor to the
step-up pulse transformer. The inductor passes the 24
Volts without shorting the return pulse.
5:1 Pulse
Transformer
2981 or Equivalent
(PNP Driver I.C.)
8 Probe
Connections
49.9K
Metal Film
GND VCC
+24 VDC
1 mH.
150
0.1 uF.
VCC
GND
5 Volt Logic
Probe Select Lines
(only one line is
active at a time.)
Latch
Microcomputer
s