Randal,
I assume that you have a vxi-mxi-2 board and want to know if there is a command to set the signal polarity when mapping a signal from the TrigIn to one of the TTL trigger lines on the backplane.
If this is the case, please see the following:
With NI-VXI 2.x, it was possible to inverse the TRIG IN signal internally before mapping it to the TTL trigger line using either TrigExtConfig or MapTrigToTrig. The Trigger Configuration Functions were supported under NI-VXI 2.x, but are no longer supported under NI-VXI 3.0, 3.1, 3.2.
Currently, NI-VXI 3.0, 3.1, 3.2 supports the function MapTrigToTrig() from the NI-VXI API and its NI-VISA equivalent function viMapTrigger. Under NI-VXI 3.2, not all of the features of these two functions are supported. However,
in future versions of the NI-VISA and NI-VXI driver, the argument "mode" of the function will be supported. This argument allows to invert the signal that comes from a trigger before mapping it to a TTL tirgger line in the backplane of a VXI chassis.
For more information on trigger mapping and inversion, please see:
How to Map Triggers Using VXI-MXI-2 and NI-VXI 3.0, 3.1, or 3.2: http://digital.ni.com/public.nsf/3efedde4322fef19862567740067f3cc/b05466083f58dba686256a9a0070e0c5?OpenDocument
NI-VXI User Manual: http://digital.ni.com/manuals.nsf/websearch/80462709452087E98625665F00700049?OpenDocument&node=132100_US
NI-VXI Programmer Reference Manual: http://digital.ni.com/manuals.nsf/websearch/4C95BFE19CAFE4248625665F0070B146?OpenDocument&node=132100_US
NI-VISA User Manual: http://digital.ni.com/manuals.nsf/websearch/266526277DFF74F786256ADC0065C50C?OpenDocument&node=132100_US
NI-VISA Programmer Reference Manual: http://digital.ni.com/manuals.nsf/websearch/10955BAA9
92050E386256ABF005AE1AC?OpenDocument&node=132100_US