can I use differnet patterns for a "digital pattern match start trigger"

[tt_ni]

Hello,

Currently I would like use different patterns for a trigger the PCIe-6537 board to start capture data, for example, two patterns: 1101 and 1100 in digital IO lines line0:3, whenever one of this two pattern happens, start capture.

It seems like "digital pattern match" in DAQmx trigger can use one pattern only.

thanks!

[Wayne.C]

Your two triggers can be logically reduced to the following single trigger.        110X

[tt_ni]

Sorry.  that is just a example, and in this example, I make something wrong. What I am actually thinking about is, 1100 and the other is the reverse 0011, then is it possible any one of them happens will give a pattern match, and trigger the capture of data? thanks.

[Wayne.C]

That's a 5 star question and I don't know the answer.   Unfortunately I don't have any DAQmx hardware around at this time to even play with.

[tt_ni]

anybody can help? if NI don't support this feature, it is realy a pity.

however it could be good if there are any ways to work around?

[Wayne.C]

How fast do you need to acquire samples?  It might be possible to work up something that analyzes the data as it is acquired and then grab the data that you want.  Not as slick as the Task trigger but it should work.

[tt_ni]

I guess it is not, as the pattern is coming along with the data, thus any software trigger will cause data lost, and won't be accepted.

[Mark_E]

Hi tt_ni,

Pattern I/O only allows the acquisition based off of one pattern. This is a “limitation” of the hardware based on the registers being set a certain way and monitoring a change from that. You could add external circuitry to OR your patterns and based the pattern I/O off of the output of that external circuitry. The other option is to look at an FPGA option.