3. External Connection
32
DI-64T2-PCI, DO-64T2-PCI
Connecting Input Signals
Input Circuit
* I-xx represents an input pin.
One polyswitch is connected for Vcc(+5V) terminal.
Figure 3.6. Input Circuit < DI-64T2-PCI >
The input circuit of interface is illustrated in Figure 3.6.
External digital signals given to signal inputs are TTL levels. The individual input signals are passed
to the personal computer as negative logic signals. As each of the signal inputs is pulled up internally,
the output of a relay contact or semiconductor switch can be connected directly between the signal input
and the signal common pin.
Connecting a Switch
When the switch is ON, the corresponding bit contains 1.
When the switch is OFF, by contrast, the bit contains 0.
Figure 3.7. An Example to use Input I-00 < DI-64T2-PCI >
External device
Input pin
Signal
common
Vcc
+5V output
GND
GND
Vcc
74ALS541
Board
10kW
Over current
protection
GND (CN1 : A01 pin)
B
oa
rd
I-00 (CN1 : A03 pin)
Switch
