National Instruments NI 9421

© National Instruments Corp. 11 NI 9421/9423
The NI 9421/9423 channel registers as ON when the
sourcing-output device applies a voltage or drives a current that is
in the input ON range to DI. The channel registers as OFF when the
device applies a voltage or drives a current that is in the input OFF
range to DI. If no device is connected to DI, the channel registers
as OFF. Refer to the Specifications section for more information
about the ON and OFF states.
Each channel has an LED that turns on and off to indicate the state
of that channel. When a channel LED is lit, the channel is on. When
the LED is dark, the channel is off. The LEDs are disabled when
the chassis is in sleep mode. Refer to the Sleep Mode section for
more information about sleep mode.