How to synchronize two devices with DAQmx base 2.0 (mac osx)

[tibobo]

Hi Alan,

"I just tested with 2 M Series boards on a Mac OS X, using the RTSI program you posted, and everything worked fine."

I didn't mentioned I tested it with one M serie and one S serie board. It could explain it didn't work for me.


"Do you have an NI RTSI cable, or are you using another cable (some cables of that type swap some lines)?
Yes, it's an NI RTSI cable.


"Can you look at the signal on RTSI1 to see if it is there?"
I didn't. I wasn't sure to be able to see anything. Anyway, I don't have any oscilloscope, but I could do it with the analog input of the other board !

"When you run it, do you get any errors? "
I get a "timeout" error from dev2 read vi.

"What devices do you have? "
M serie PCI 6284 and S serie PCI 6143


The link to the ni webpage
http://zone.ni.com/devzone/conceptd.nsf/webmain/42B73A7B82F0FEC786256FB1007227EC

I'll check if I get something on the RTSI1 port on monday.

Thanks for the help !

Boris

[AlanArmstead]

Ok, what device are you using for the 'master'?  We know for sure that you can export the sample clock to RTSI with an M Series device, additionally, we know that you can use an external ai sample clock (on RTSI) with an M Series.  So I would suggest trying the M Series as the master and slave.  So, if either of those two operations work with your S Series board, then you should be good to go.

-Alan A.

[tibobo]

Hi Alan,

Ok, after many tries...it works !

I think that the RTSI cable was misconnected. (I've got a Powermac G5 and there is not a lot of space in the neighborhood of the boards).

I was able to achieve RTSI sample clock sharing, RTSI triggering, PFI sample clock sharing and PFI triggering (for other users, see the example I gave before and please ask if you have any problem).

However, I'd like to share the 80MHz internal clock to do 50 kHz DAQ on the S serie board and 100 Hz DAQ on the M serie board. As far as I tried, I only achieved to share the "sample clock", meaning that both DAQ tasks must have the same sampling rate.

Do you think that there is a mean to do that ?

Boris

[AlanArmstead]

It isn't possible to share the internal clock with NI-DAQmx Base.  The signals that can be exported are: ai sample clock, ai convert clock, ai start trigger, ai reference trigger, ao sample clock and ao start trigger.  So, without some additional programming, yes, your devices will have to acquire at the same rate.  However, there are some things you could do to work around this, like run a 'dummy' ao task and export the ao sample clock, or use the ai convert clock as the other devices sample clock, etc.

-Alan A.

[tibobo]

Thanks for your help and for the tips !

Bye

Boris