SignalExpress: System logs for 5 minutes, then terminates with "Sample period too short"

[JKSH]

Hi all,

I'm puzzled by this issue. My customer has a very simple SignalExpress acquisition task (20 channels, acquired once every second) for a networked cDAQ chassis. The Acquisition Mode is "1 Sample (On Demand)", and  Sample Period (s) is "1".

The system will happily log away for about 5 minutes, and then stop with an error. Screenshot below (see http://forums.ni.com/t5/image/serverpage/image-id/137424i1AC14B4DDC907A91/image-size/original?v=mpbl...for the full version)

When I click "Details", I basically see this error message: http://digital.ni.com/public.nsf/allkb/9430D7F074BE8577862577300063CE97 -- it says there was a bug in DAQmx 9.0, but should be fixed in later versions.

However, we're seeing this issue on 2 different PCs, (using same cDAQ chassis)

Original PC:

• Windows XP
• SignalExpress 2011
• DAQmx 9.4

New PC:

• Windows 7
• SignalExpress 2013
• DAQmx 9.7.5

Any ideas?

[DollaBrillz]

What happens if you change the Acquisition Mode to Continuous Samples?

Best Regards,

[JKSH]

Hi R. Brill,

When I changed the Acquisition Mode to Continuous Samples, it logged without errors (tested for ~15 minutes). However, that's not a good solution because Continuous Samples forces my Charts to become Time Graphs, which doesn't let me see my full data history in real time.

The system is a cDAQ-9188 with 2 modules: NI-9207 (voltage input) and NI 9213 (thermocouple input)

I tried other things:

• I ran the project on two different chasses (cDAQ-9188 and cDAQ-9172) -- both showed the same error, so the issue is not in the chassis.
• I acquired from the NI-9207 only -- There were no errors after 15min
• I acquired from the NI-9213 only, logging channels 0 to 7 only -- There were no errors after 15mins
• I acquired from the NI-9213 only, logging channels 8 to 15 only -- There were no errors after 15mins
• I acquired from the NI-9213 only, logging all channels -- After 5mins, logging was aborted with the "Sample period too short" message.

This suggests that the issue is in the thermocouple DAQ, somehow. What's going on? The NI 9213 is a high-speed module, sampling 16 channels at 1 Hz should be no problem, right?

[DollaBrillz]

What operating system are you using and how much RAM do you have? if you open up the Task Manager (Ctrl+Alt+Del) and select the processes tab, what is your total memory usage before beginning your acquisition and what is it as the program is returning this error? It could be that you are running into a memory issue.

Best Regards,

[JKSH]

The original PC is Windows XP 32-bit with 2 GB RAM, the new PC is 64-bit Windows 7 Pro with 4 GB RAM. On both PCs, the error appeared after running for 5 minutes.

Due to some circumstances I won't be able to access the system for a while, but I've attached the .seproj file -- it's a very simple setup which logs 20 channels at 1 Hz. I cannot imagine it running out of memory in 5 minutes.

Can you please try it if you have similar hardware? All you need is a cDAQ chassis (I used a cDAQ-9188 and cDAQ-9172) and an NI-9213.

[DollaBrillz]

Thanks for the information. Are you running the 9213 in high speed or high resolution mode? If you configure this same task in NI MAX do you encounter the same error? Also, do you know exactly how many samples have been logged when the error occurs? How many samples are you expecting to read?

Let me know what you find!

Best Regards,