3. External Connection
48
DIO-6464T2-PCI,
DI-128T2-PCI,
DO-128T2-PCI
Connecting Input Signals
Input Circuit
External device
Input pin
Signal
common
Vcc
+5V output
GND
GND
Vcc
74ALS541
10kW
Board
PolySwitch
* I-xx represents an input pin.
One polyswitch is connected for Vcc(+5V) terminal.
Figure 3.11. Input Circuit
The input circuits of interface blocks of the < DIO-6464T2-PCI > and < DI-128T2-PCI > are illustrated
in Figure 3.11.
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
GND (CN1 : A1 pin)
Bo
ar
d
I-00 (CN1 : A7 pin)
Switch
When the switch is ON, the corresponding bit contains 1.
When the switch is OFF, by contrast, the bit contains 0.
Figure 3.12. An Example to use Input I-00
