User Manual

CrossCheck CDPD Mobile Unit Manual
41
Installation
2
2.9.7
Pulse Counting Inputs (Pulse 0 to Pulse 2)
The CrossCheck CDPD also supports three pulse-counting inputs that
can be used in several applications. The circuit diagram is shown in
Figure 2.19.
Figure 2.20 Pulse Countin Input Circuit Diagram
Input Logic High:
Open circuit or V
in
> 2.4 VDC
Input Logic Low:
V
in
< 0.6 VDC
The inputs must remain in either state for at least
200 milliseconds before the CrossCheck CDPD
detects the input.
Input Current
(Max)
I
in
< 3 mA
1 mA is typical at 12 VDC.
Minimum Pulse
Width
500 microseconds
Input Protection:
Protected up to at least V
Batt
continuous
3K
330K
0.01µF
To logic
470pf
Input
100K
3.3V/0.5/A