Measurement Computing USB-DIO96H, Руководство пользователя, Страница: 17 / 27

USB-DIO96H User's Guide Functional Details
Digital I/O terminals (FIRSTPORTA Bit 0 to FOURTHPORTC Bit 7)
You can connect up to 96 digital I/O lines to the four banks of screw terminals (Port 1 to Port 4). Connect up to
24 DIO lines to each screw terminal group:
!
Connect up to 24 FIRSTPORT signals to the screw terminals labeled
PORT 1
.
! Connect up to 24 SECONDPORT signals to the screw terminals labeled
PORT 2
.
! Connect up to 24 THIRDPORT signals to the screw terminals labeled
PORT 3
.
! Connect up to 24 FOURTHPORT signals to the screw terminals labeled
PORT 4
.
You can configure each digital port for either input or output.
When configured for input, you can use the USB-DIO96H digital I/O terminals to detect the state of any TTL
level input.
shows the USB-DIO96H wired to detect the state of a switch. When you set the switch to
the
+5 V
position, FIRSTPORTA Bit 0 reads TRUE (1). When you move the switch to the
GND
position,
FIRSTPORTA Bit 0 reads FALSE (0).
Figure 3-2
Figure 3-2. Digital connection of FIRSTPORTA Bit 0 detecting the state of a switch
A schematic drawing of this switch connection is shown here.
+5V +GND
FIRSTPORTA Bit 0
Figure 3-3. Schematic showing switch connection to digital channel FIRSTPORTA Bit 0
Output (sink) current limits
Each DIO pin can sink 64 mA maximum when configured for output.
Output (source) current limits
Each DIO pin can source 24 mA maximum when configured for output. The USB-DIO96H can source a
maximum 2.6 A, total.
For more information on digital signal connections
For information on digital signal connections and I/O techniques, refer to the Guide to Signal Connections
(available on our web site at www.mccdaq.com/signals/signals.pdf ).
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