Hi Folks:

I'm trying to do some fairly straightforward communication with the PXI 6534, although there are some somewhat subtle issues:

* external Clock
* repetitive, but not continuous operation.
* simultaneous triggering of output with input from a PXI 6133, and (at other times) triggering of input with output from a PXI 6733.

At this point, I'm not looking for help on any of the specifics, but hoping to find someone who has been down the 6534 path ahead of me that might be able to make suggestions on where to get the information I need to work things out for myself.

I find the DAXmx manual for this card more than a little cryptic. I'm starting to read the Traditional NiDAQ, which seems much more comprehensible, but I'm not sure the degree to which what I learn from that will help me with DaqMX, or alternatively whether I can use traditional NiDAQ to control the 6733 without rewriting all the code for my analog boards, which will share trigger lines with the 6534.

I also haven't yet found a good narrative description of how to deal with sharing of trigger lines between stuff on the PXi rack.


I'm taking a look at some of the links in this thoughtful & helpful post by Neville in an old thread:
Neville's Post

but if anyone else has suggestions I'll be very grateful.

Thanks & Best Regards, Louis

Hi Louis,

I'm glad you found my post useful, but I am not sure which one you are referring to, since the link in your post is broken.


Its been a while since I did any DAQ, but I found that DAQmx is a super-set of the old DAQ capabilities. So whatever you learn reading the old DAQ manual should be applicable in the new DAQmx API.

Note that you cannot use both API's simultanously. You have to disable one of them to use the other. There is a VI on the pallets somewhere that does that.

DAQmx definitely isn't as well documented as the old stuff, but it is much more powerful and the multi-threaded nature of the driver allows you to do things which you couldn't before: for example software timing of DAQ applications is much more robust and faster than before. You can fake simultanous analog input and output using software timing on cheaper DAQ cards that only have a single DMA channel.

I'm not sure that there is a neat way to share the trigger lines except using a breakout board accessory for each device and hardwiring the lines from the different modules. Take a look at this KB entry and this other one, talking about RTSI lines in PXI


Neville.

For others, another try at linking to Neville's post:

http://forums.lavag.org/index.php?s=&s...post&p=6013

Not sure why I can't get the regular style link to work, but copy and paste above might work.

Hi Neville:

Thanks for getting back to me. Helpful advice. Seems like the best thing to try is to read the old DAQ manual to form a basis of understanding for the more cryptic DAQmx documentation, but to stick with DAQmx.

I'm not sure that I really will have to use external breakouts to patch through my triggers-- I think the PXI rack provides the hardware paths I need, all I have to do it learn how to configure and use those paths, but I'll definitely look at the links you gave on this topic before I beat my head against the wall much more.

Again, thanks for the prompt and helpful response.

Best Regards, Louis

[edit- third try at getting link to other post to work.]