Digital acquisiton speed, it misses pulses

Hi everyone,

I am trying to make a very simple acquisiton program in wich I read a low frequency digital signal and plot the results. The problem I have is that the acquisition doesn't seem to be fast enough for the application, as it misses many pulses at 80 Hz approximately. I don't understand why, the frecuency is very low and with an Advantech PCI 1711 Board this should't be happening.

Here is the program

dio = digitalio ('advantech',0)
hwlines = addline(dio,2,'In')
tic
for i=1:600
   out(i)= getvalue (dio)
save('datos.txt','out')
end
tiempo=toc
stairs (out)

Thanks a lot in advance

Alejandro

[ayam mohsen]

hello,what version of matlab using with pci-1711,i am also using pci-1711 but toolbox not link with it,please help me,thank yoy

[Walter Roberson]

Ayam, are you using a 32 bit MATLAB and using the legacy interface?

https://www.mathworks.com/products/daq/supported/advantech.html

There is a bugfix for MATLAB R14 for the 1711; see http://www.mathworks.com/support/solutions/en/data/1-P4NML/index.html?product=DA

[ayam mohsen]

hello,i am using matlab 2007 and iam trying to use digitalio object to communicate with pci-1711u,by following dio = digitalio ('advantech',0) error will be Error using ==> digitalio.digitalio Error using ==> digitalio.digitalio Attempt to divide an integer value by an integer divisor of zero. please help me ,how i can handle this error and also i am made register for advantech by daqregister('advantech')

[Walter Roberson]

The only references I can find for that error message are associated with needing a graphics driver upgrade (!)

Check also your driver release http://www.mathworks.com/support/solutions/en/data/1-P4NMX/index.html?product=DA which appear to be available at http://support.advantech.com.tw/support/DownloadSRDetail.aspx?SR_ID=1-94QHP&Doc_Source=Download (towards the bottom); you might also need the device manager just above that.

[ayam mohsen]

thankyou,i up date the driver of pci and of daq ,but error not correct

[Walter Roberson]

Perhaps your graphics driver needs to be updated?

I would normally suggest that you contact support, but I know you aren't going to have a support contract on R2007!

[ayam mohsen]

what version of matlab you see to used with pci-1711u notice ,i found just matlab 2008 and 2007 can see the pci-1711u using real time window target simulink

[Alejandro Martín]

Hi Ayam, I use a R2010a version of Matlab in a 32 bits Windows XP, and it works with PCI 1711 (note that PCI 1711U is different from PCI 1711). It also works with real time windows target. I don´t know what you are trying to do but if you let me know maybe I can help you if you are stuck in something.

Answer 1

[Walter Roberson]

It is not recommended to save() within the loop. save() can take a fair bit of time.

[Alejandro Martín]

Thanks a lot Walter, I worked with your suggestion.