output overshooting and undershooting problem of PCI-6534

[yibo]

Hi,

I'm using the digital outputs from PCI-6534 to control varies devices, like shutters,CCD camera. But actually the output is not a clean TTL signal, several snapshootes are attached below.

I also try to terminate each output channel with schottky diode following the same scheme in the manual. It does not work somehow.

What could be the reason for this problem? Does this indicate the hardware itself is broken?

Any help would be appreciated

Cheers,

Yibo 

[4Matted]

Yibo,

It appears to me your device is working and is outputting a TTL signal but you are experiencing ringing as well as overshoot errors. Here is an older archived KB I was able to find that discusses this. http://digital.ni.com/public.nsf/allkb/7BE799A204AC77CF86256C3E007593BC?OpenDocument. In terms of you signal it does not look broken. It simply appears as though you are experiencing overshooting and ringing. Is this causing problems when connected to your system? 

[yibo]

Hi Matt,

Thank you for your reply. It turns out that when you try to terminate the output chennal you have to make the diode termination very close to the load. I attached my latest result, it looks improve quite a lot. Regarding your question, yes, it does cause problem sometime. My labview program will lock up, then the card (PCI-6534) can not pass the self-test with NI MAX and show Error -200020. I have to restart computer. We  are still not clear which part triggers the crash. It is quite annoying.  

Cheers,

Yibo

[4Matted]

Yibo,

Just to clarify is the error still occurring or did placing the diodes closer to the load solve your issue? If the issue is still occurring it may be worth resetting you MAX Configuration Data, directions for this can be found here. http://digital.ni.com/public.nsf/allkb/2C7480E856987FFF862573AE005AB0D9?OpenDocument

[yibo]

Hi Matt,

Follow your suggestion, I reset the Configuration Data and also update DAQmx. It looks pretty good so far. Let's see how long the program can run this time.

Thanks a lot.

Cheers,

Yibo