Digital trigger in cdaq 9172

[Roy.a]

Hi,

I am setting up a continuous temperature measurement task using TC module 9213 and K type thermocouple. The acquisition starts using a Digital trigger. Pretty simple. 

I am using a cdaq-9172 8 slot chassis and what I have learnt that for PFI trigger operation, I can use slot 5 and 6 using any digital input module or NI 9205 PFI0 line in any slot position. I have NI 9423 DI module and NI 9205 AI module with PFI0. 

The problem is I have tried both these options as a digital trigger (NI 9205 in any slot and NI 9423 in slot 5 or 6), but none works! There is no issue in the labview code as it works without trigger and with trigger if I use NI 9188 chassis. 

Am I missing something?

Thanks!

Roy

[JayJayHella]

Hi Roy,

Could you please give us a screenshot of your code, so we can see how you are exporting your trigger to the 9213? 

[Roy.a]

Jake,

Thanks for responding.. Here is the vi snippet

 

We are continously acquiring data started from a digital trigger and comparing with a threshold value if it has crossed or not..

Best..

Roy

[JayJayHella]

Hi Roy,

Have you look at grounding your singal to the COM? This has been known to cause problems with the 9205.

Using the Digital Output and PFI Lines of the NI 9205/9206 with CompactDAQ

http://digital.ni.com/public.nsf/allkb/51DD3F0206860ABC8625724B007364C9

[Roy.a]

Yes, I have tried connecting the COM to the external trigger source (OMEGA PST 4130 with 5V output power setting and a switch) ground. The trigger in case is very inconsistent, often it doesnot work or triggers even when the switch is in OFF position. The trigger is highly unreliable.

This is the case for using both NI 9205 (in slot 1) and NI 9423 (slot  6). 

Can there be other issues other than grounding?

Thanks,

Roy

[JayJayHella]

Hi Roy, 

Thank you letting me know that you have already looked into grounding. I am wondering if there is something wrong with the chassis? Do the exact same cards work in another chassis such as your 9188? Do you have another 9172 chassis that you can try? 

[Roy.a]

The cards work fine on the 9188 chasis in terms of analog input (9205) and Digital input (9423) signals. 

This is what I have tried-

In stead of the Omega PST 4130 power supply, I used a battery pack (8 AA batteries) and connected the COM with battery pack negative end wire and triggered the positive wire end of the battery pack manually with the PFI0 of 9205 and PFI7 of 9423 both. 

In both chassis (9172/9188) the 9423 PFI7 works fine as a trigger and is consistent. However, 9205 PFI0 trigger doesn't work in either 9172 or 9188.  

The Omega PST 4130 is a much more reliable power source than a regular off the shelve battery pack. But triggering is highly inconsistent or doesn't work at all in both chassis.

Any clue what is going on? Even if I don't use the omega power supply, still the 9205 module PFI0 is not working as a trigger. 

Thanks,

Roy

[JayJayHella]

Hi Roy,

Are you PFI0 to import or export the trigger? PFI0 can only be used to import triggers; it cannot output or export signals.It is possible that something may be wrong with the card. You can create a service request with using your MyNI account and an Applications Engineer can help you decide if you need to RMA you device.