User`s manual

RabbitFLEX User’s Manual www.rabbit.com 39
4.3.10.4 Contact Input
This section presents the circuit schematic and the characteristics for the contact input.
A contact input is designed to be connected to a switch. It has a longer time constant than the other digital
inputs to quiet the noise generated by a switch closure. And it already has the pullup allowing simple wir-
ing of the switch between the input and ground.
Basically, it is a hardware switch debouncer, though it may
be still be neccesary to use software to fully debounce the switch.
Figure 4-14 Contact Input Circuit
Table 4-11. Contact Input Characteristics
DIGITAL INPUT, CONTACTS
VERSION 6.01
4.7 kW
R4A
470 W
+5 V
C1
100 nF
I/O
Pin
Digital Interface
Cell
R5
Symbol Parameter Note Min Typical Max Unit
V
IW
Working Input Voltage 0 5 V
V
IM
Maximum Input Voltage -0.5 10.5 V
V
IH
High Level Input Voltage 2.0 V
V
IL
Low Level Input Voltage 0.8 V
V
T
Trigger Threshold Voltage 1 1.4 V
I
IH
High Level Input Current 2 -6.4 mA
I
IL
Low Level Input Current 3 -8.9 mA
I
I
Input Current 4 -13 13 mA
I
QH
High Level Quiescent Current 2, 5, 6 6.4 mA
I
QL
Low Level Quiescent Current 3, 5, 6 8.9 mA
t
I1
Input Time Delay to 1 7 240 uS
t
I0
Input Time Delay to 0 8 780 uS
Note 1: (V
IH
+ V
IL
) / 2
v1.03
Note 2: at V
IH
cell v6.01
Note 3: at V
IL
Note 4: Over Maximum Input Voltage range
Note 5: From PowerCore Supply5
Note 6: I
Q
= ((5 - V
IW
) * 2.13) mA over Working Input Voltage Range
Note 7: Time delay from contact opening to see V
IH
at the cell output
Note 8: Time delay from contact closing to see V
IL
at the cell output
DC
AC