Rabbit Smartcat, User Manual

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20 Smartcat (BL2100)
3.2 Digital I/O
3.2.1 Digital Inputs
The BL2100 has 24 digital inputs, IN00–IN23, each of which is protected over a range of
–36 V to +36 V. The inputs are factory-configured to be pulled up to +5 V, but they can
also be pulled up to +K2 or down to 0 V in banks of eight by changing a surface-mounted
0

resistor as shown in Figure 9.
Figure 9. BL2100 Digital Inputs [Pulled Up—Factory Default]
NOTE: If the inputs are pulled up to +K2, the voltage range over which the digital inputs
are protected changes to K2 – 36 V to +36 V.
The actual switching threshold is approximately 2.40 V. Anything below this value is a
logic 0, and anything above is a logic 1
.
The digital inputs are each fully protected over a
range of -36 V to +36 V, and can handle short
spikes of ±40 V.
Figure 10. BL2100 Digital Input
Protected Range
1 nF
100 k W
27 k W
Rabbit 2000™
Microprocessor
Factory
Default
Vcc
GND
+K2
0 W
+40 V
+36 V
+3.3 V
–40 V
Normal Switching
Levels
Spikes
Digital Input V
oltage
Spikes
Spikes