National Instruments NI 2590/2591 - Manual (Page 21)

Chapter 2 NI 2590/2591 Operation
© National Instruments Corporation 2-7 NI 2590/2591 User Manual
intervention. You can configure the switch module to process the scan list
once or to continuously loop through the scan list.
PXI Interface
You can configure and control your NI 2590/2591 switch module through
the PXI interface, taking advantage of PXI features. The NI 2590/2591
uses the PXI TTL triggers to synchronize scanning with a measurement
device such as the NI 5102 (PXI) 20 MS/s oscilloscope, or the NI 5411
for PXI arbitrary waveform generator.
PXI Triggers
External Trigger Input
The NI 2590/2591 can use an external trigger input to advance between
scan setups in a scan list. Using the driver software, you can configure the
switch module 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 module.
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.
Scanner Advanced
The NI 2590/2591 can generate a scanner advanced trigger to indicate
when the switch module is set up and ready to take measurements. Using
the driver software, you can configure the switch module to route the
scanner advanced (SCANADV) trigger to any PXI TTL trigger line or to
the PXI star trigger. You can configure the switch module to generate the
SCANADV trigger when a relay has settled (or debounced).
Because the NI 2590/2591 has open-collector drivers on the PXI TTL
trigger lines, you can have multiple switch modules using the same trigger
line in the multiboard SCANADV mode.