User`s manual

PK2100
3-6 s I/O Configurations
Multiple contacts may be connected with external resistors to a single
universal input (Figure 3-5).
+10-V ref
3.3 kΩ
1 kΩ
+10-V ref
3.3 kΩ
4 kΩ 2 kΩ 1 kΩ
Figure 3-5. Use of External Resistors to Connect Multiple
Contacts to Single Universal Input
(b) Muliple Contacts Resolvable
Individually
(a) Multiple Contacts (closest has
priority)
Digital Inputs
The seven digital inputs accept an input voltage with a digital threshold at
approximately 2.5 volts. The inputs are protected against overload over a
range from -48 to +48 volts. These inputs are convenient for detecting
contact closures or sensing devices with open collector transistor outputs.
Logic-level outputs can also be detected as long as they are supplied from
CMOS logic outputs guaranteed to swing to at least 3.5volts. Three of
the digital inputs are shared as inputs to the high-speed counters.
Figure 3-6 shows a digital input. The RC circuit helps to stabilize the
input, but note the 0.2-millisecond RC time constant, which affects signals
faster than 5kHz. While it may be tempting to disable the capacitor with
a jumper, this is not recommended because the signal may be degraded.
0.01 µF
Digital InputInput
+5 V
10 kΩ
22 kΩ
Figure 3-6. PK2100 Digital Input