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Chapter 2
NI 2565 Operation
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National Instruments Corporation
2-5
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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 runs 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.
The onboard control logic for the NI 2565 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 2565 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.
PXI Interface
The NI 2565 switch card has a PXI interface through which you can use
your driver software to configure and control the card. The NI 2565 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 2565 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 or
the PXI star trigger. Alternatively, you can use a software command to
trigger the switch card.
All external trigger lines are compatible with TTL voltage levels and are
edge sensitive. The minimum pulse width from the PXI TTL triggers and
PXI star trigger is 70 ns.