Thanks for replying. In fact I had already managed to figure this out for myself (after posting the request for help) - niDMM Fetch Multi Point.vi calls a DLL which presumably contains the buffer that is being filled - there is no obvious way of increasing its size.
This does imply that if you are reading one data point every minute that you are in fact reading old data (i.e. > 1 min old) - I'm not sure I understand why NI would set things up that way.
Anyway, I've now modified my code so that it reads data from the card as fast as possible (~0.2s at 6 1/2 digits) then simply throws away the data points in between those that I want to keep.
Hi. I've the sam problem but using ni DMM Read Multipoint just.
This buffer over write error appear after 30 mins, or 6 hours or 2 days, so I can't know if the problem is over, for evrery change I do.
Also I try to set buffer size, until 16Mb (maximum buffer size for NI PXI-4065 DMM slot).
How can I resolve this issue? What can I try too?
For others informations I have to read continous voltage DC values from a photovoltaic complex system, about 30 channels, and only one AC channel.
12 of these work with a DC voltage range 0-50mV, the others DC channels with a voltage range of 20-200V.
The AC channel have to read a 5-20 mV voltage.
Can you post your code? Also, can you try running Cont Acq & Chart Multiple Samples.vi in the Example Finder and see if the error occurs then?
Hi, thank you for your answer.
In the attachment there is the code "ikube 2.1.vi". In this moment our PXI is in national Instruments customer care for testing, So now I can't try your help vi.
I am going to try to reproduce the issue on our end here. I had a few questions that should help us get us going...
1. What switch card are you using?
2. What version of DMM are you running?
3. I noticed that your code looks very similar to our example, to niSwitch DMM Switch Handshaking.vi. In your code however you are using niDMM Read Multipoint instead of niDMM Fetch Multipoint. Was there a reason you used Read instead of Fetch?
I hope to have feedback for you later this week and will let you know what I find then.
I ran a test over 2.5 days and was not able to reproduce the error on my system. I assumed you were running a 2527 Switch as this was the default topology in your pull down menu on your front panel. Although it does not appear to have made a difference in my testing, I would suggest calling the niDMM Read Multipoint before calling niSwitch Initiate Scan. This way we can ensure that when the Switch sends out the first trigger at niSwitch Initiate Scan, it will be received by the DMM because the DMM has been set up beforehand. If you look at the NI Switch DMM Switch Handshaking.vi in the Example Finder, you will notice that the DMM is initiated first before the Switch.
You may also consider updating your driver if you haven't already to 3.0.5 in case there have been any improvements relating to this issue. 3.0.5 is the version I ran for the test on my end. Please let me know if you run into any problems after upgrading and swapping the positions of the two VIs.