Chapter 3 Signal Connections
© National Instruments Corporation
3-11
PC-DIO-96/PnP User Manual
Low DIO Power-up State
If you select pulled-low mode, each DIO line will be pulled to GND
(0 VDC) using a 100 k
Ω
resistor. If you want to pull a specific line high,
connect a pull-up resistor that will give you a minimum of 2.8 VDC.
The DIO lines are capable of sinking a maximum of 2.5 mA at 0.4 V in
the low state. Use the largest possible resistance value so that you do
not to use more current than necessary to perform the pull-up task.
Also, make sure the pull-up resistor value is not so large that leakage
current from the DIO line along with the current from the 100 k
Ω
pull-
down resistor brings the voltage at the resistor below a TTL high level
of 2.8 VDC.
Figure 3-6. DIO Channel Configured for Low DIO Power-up State with External Load
PC-DIO-96/PnP
Digital I/O Line
82C55
+5 V
GND
100 k
Ω
R
L
Содержание PC-DIO-96/PnP
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