Keithley KUSB-3160, User Manual

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Chapter 2
8
Digital I/O Lines
The KUSB-3160 module supports 64 shared digital I/O lines. These
lines are organized as eight digital banks (banks 0 to 7)), each
containing eight digital I/O lines (lines 0 to 7).
The KUSB-3160 module also supports 32 dedicated digital input
lines. These lines are organized as four banks (banks 8 to 11), each
containing eight digital input lines (lines 0 to 7).
You access the digital inputs through the digital input (DIN)
subsystem and the digital outputs through the digital output (DOUT)
subsystem.
The inputs are pulled up to +5 V through a 100 k
Ω
resistor. You can
choose to debounce the inputs using the Open Layers Control Panel.
When debounce is selected, a debounce delay of 5 ms occurs before a
change is passed through the digital filter on the module. When
debounce is not selected (the default configuration), a delay of less
than 1 ms occurs. Refer to the
KUSB-3160 Getting Started Manual for
more information.
Outputs are open collectors with a 100 k
Ω
resistor connected to the
internal is5 V. All outputs are diode-protected for back EMF
voltages typically seen when driving relays. The output stage latches
are normally powered by the module. However, you can externally
power the +5 V output so that the digital outputs retain their current
values when the module is powered down.
Note: +5 V output is available only when one of the subsystems is
activated, which, in turn, activates power to the module.
The KUSB-3160 provides enough current to drive only one LED per
output line on the KUSB-STP100 screw terminal panel at a time. An
LED turns on when the output is low.