sync two arbitrary DAQ cards

[GabrielaK]

Hi,

I am writing a driver VI which is supposed to work with any DAQmx compatible DAC card. To synchronize analog input and output, I have used "Get terminal name with device prefix" (input: ai/StartTrigger) and have connected its output to DAQmx Start Trigger (digital edge) of the output channel. Then I start both tasks and they are synchronized - that works fine as long as input and output channel are on the same device.

The problem is: our customers could also use two different cards for input and output. In that case error -89125 occurs (No registered trigger lines could be found between the devices in the route.). I do NOT know which cards the customer has (of course I can find out programmatically, but it can be two E-series cards, two M-series cards, one E and one M-series card, or whatever configuration he has). He may even use PCMCIA cards which do not offer a RTSI line. Is it possible to implement a "general" trigger function" that works with every configuration???

I am using LabVIEW 7.1 with DAQmx 8.3.

Best regards,

Gabs

[nikolair]

Hi Gabs,

the different DAQ series support also different possibillities for synchronization. RTSI is one solution that works over different DAQ cards, but cannot be used for devices which don't support that feature. Maybe you can use a general clock signal for synchronizing the different DAQ cards which is created by an counter output of one card, therefore you have to use external connections instead of a RTSI cable.
See also the following KB link to that: http://forums.ni.com/ni/board/message?board.id=250&message.id=25329

For a general application you have to implement all possibillities of your synchronisation mechanisms. For most of them are example VI's available in the LabVIEW example library.

The NI Developer Zone describes also many synchronization mechanisms, here are some importent links that might be helpful:
http://zone.ni.com/devzone/cda/tut/p/id/4322
http://zone.ni.com/devzone/cda/tut/p/id/3615

regards,

Nikolai

[GabrielaK]

Hi Nikolai,

thanks for your answer, that is what I was afraid of... The link to the "Timing and synchronization" article was very interesting, thanks for that. Unfortunately, the KB link directs me to my own thread - could you please check the link??

Thanks a lot in advance,

best regards,

Gabs

[nikolair]

Hi Gabs,

I'm sorry... here's the correct link: http://digital.ni.com/public.nsf/websearch/8683A17AED4FDBAB86256C1E006D3BBA?OpenDocument

regards,

Nikolai

[GabrielaK]

Thank you, Nikolai!

Best regards,

Gabs