National Instruments 321906B-01 用户手册
Chapter 2
NI 2501/2503 Operation
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Generate a scanner advanced trigger
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Generate a breakpoint interrupt
You can use the driver software to configure the switch card for continuous
or one-time scanning. In continuous scanning, the switch card cycles
through the scan list until you disable scanning. For one-time scanning, the
switch card cycles through the scan list only once.
or one-time scanning. In continuous scanning, the switch card cycles
through the scan list until you disable scanning. For one-time scanning, the
switch card cycles through the scan list only once.
You can also use software commands to clear the scan list or reset it to the
beginning at any time.
beginning at any time.
The onboard control logic for the NI 2501/2503 switch card gives you
direct access to open and close the relays, and also the capability to
download up to 1024 random scanning instructions. The software included
with the card automatically configures the NI 2501/2503 and downloads
the scan list to hardware for you. The scan list itself downloads directly into
the memory of the card to deliver the fastest scan possible with no
controller intervention. You can configure the switch card to process the
scan list once or to continuously loop through the scan list.
direct access to open and close the relays, and also the capability to
download up to 1024 random scanning instructions. The software included
with the card automatically configures the NI 2501/2503 and downloads
the scan list to hardware for you. The scan list itself downloads directly into
the memory of the card to deliver the fastest scan possible with no
controller intervention. You can configure the switch card to process the
scan list once or to continuously loop through the scan list.
When configured to operate as a single switch card with multiple
multiplexers—such as four 6 x 1 two-wire multiplexers—the scan
architecture makes it possible for each multiplexer to have its own parallel
scan list (which must be triggered together). Also, if the switch card is
configured as a matrix, the scanning architecture scans the matrix through
a series of user-definable states.
multiplexers—such as four 6 x 1 two-wire multiplexers—the scan
architecture makes it possible for each multiplexer to have its own parallel
scan list (which must be triggered together). Also, if the switch card is
configured as a matrix, the scanning architecture scans the matrix through
a series of user-definable states.
PXI Interface
The NI 2501/2503 switch card has a PXI interface through which you
can use your driver software to configure and control the card. The
NI 2501/2503 takes advantage of PXI features. It uses the PXI TTL triggers
to synchronize scanning with a measurement device such as a National
Instruments NI-4060 PXI digital multimeter (DMM).
can use your driver software to configure and control the card. The
NI 2501/2503 takes advantage of PXI features. It uses the PXI TTL triggers
to synchronize scanning with a measurement device such as a National
Instruments NI-4060 PXI digital multimeter (DMM).
Triggers
External Trigger Input
The NI 2501/2503 can use an external trigger input to advance between
scan setups in a scan list. Using the driver software, you can configure the
switch card to route the external trigger from any of the PXI TTL trigger
lines, the PXI star trigger, or the EXT TRIG IN pin on the front connector.
Alternatively, you can use a software command to trigger the switch card.
scan setups in a scan list. Using the driver software, you can configure the
switch card to route the external trigger from any of the PXI TTL trigger
lines, the PXI star trigger, or the EXT TRIG IN pin on the front connector.
Alternatively, you can use a software command to trigger the switch card.