Using the Analog Output module in Dasylab

[dnlwthrn]

First off, I'm using Dasylab 9.00.2 on Windows XP SP3.  Hardware is IOTech PersonalDAQ 3001.

I'm trying to read a data file that was previously acquired and use the analog output on the PersonalDAQ to send the waveform to another piece of hardware.  For the moment, I am using an analog input channel to make sure that the signal is being output.  However, its not.

With the Output mode set to synchronus with continuous refill buffer and output rate set at the same as the global input rate, I get no signal output.  When I changed the output mode to asynchronous, I get what looks like a TTL "high" output partway through the file.

Can I even do this?  I can't seem to find any way to make this work.  I've also tried using a different daq system to monitor the output, and see the same thing.

Alternatively, is there a fairly simple way to set this up using the hardware I have through Labview?  I haven't tried to use the PersonalDAQ in Labview due to issues w/ the driver supplied by IOTech... 

[CJ_Butler__DASYLab_Pro]

I don't have the hardware that you are using to determine if this will work.

You will need to contact IOtech (now Measurement Computing) at www.mccdaq.com (+1 508-946-5100).  Because you're using V9, you'll be forwarded to the sales department to update to DASYLab 11. The sales team is very knowledgeable, and will help you to access whether this will work.

If you are outside of the US, you should contact your local reseller (where you bought it) for support.

You may want to download the DASYLab V11 Evaluation and the latest IOtech drivers (http://mccdaq.com/software.aspx, scroll to the bottom for the IOtech drivers), to see if it works with the current release of the software.

Have you reviewed the IOtech DASYLab Guide? The online IOtech help? You want continuous refill. You need the sample rate of the file that you're reading to match the Measurement Setup sample rate for the output, or you will underfill or overfill the buffers. 

With regard to the LabVIEW question.... IOtech/MC can answer that, since the LabVIEW drivers were developed by IOtech, not by NI. 

[dnlwthrn]

I've put in a support request already, but haven't heard anything from MCC.  I'm in the US.

What makes you think that V11 would change anything?  We've been using DASYLab since V5.5, and I'm not sure if its worth the time or $ to upgrade yet again.

I've read through all the information available.  From the PersonalDAQ User's Guide:

"Personal Daq/3000 has two 16-bit, 1 MHz analog output channels. Personal Daq/3001 has four such

channels. Analog outputs can be updated at a maximum rate of 1 MHz.

The channels have an output range of -10V to +10V. Each D/A can continuously output a waveform. This

can be read from PC RAM or from a file on the hard disk. In addition, a program can asynchronously

output a value to any of the D/As for non-waveform applications, presuming that the D/A is not already

being used in the waveform output mode."

Using Hardware Configuration (Experiment Setup/Measurements Board Settings/Driver in V9), I can get the Analog output to give me a sine wave.  Using the Analog Output module, I can manually set a voltage and it will respond.  I can't get it to respond to a stream of data points, either through Labview or DASYLab. 

[CJ_Butler__DASYLab_Pro]

Call Measurement Computing and ask for CJ.

[dnlwthrn]

I figured something out, I think.  Setting the output to asychronous, and changing the block size to 1, I was able to get the analog output to respond to a 1hz sine wave generated by the generator module.  It appears that the output only updates once every block.  However, the waveform I'm trying to duplicate was acquired at 5khz.  At that rate, the analog output module can't keep up.  Even trying to duplicate a 10hz sine wave was too much at 5khz data rate.

It looks like this isn't going to work for my application... 

[TomRizzo]

A good rule for analog outputs is that you need 20 points per sine so that it means that a 5 KHz signal you need a 100 KHz output setting.  Now, even though you collected the siganl at 5KHz, is it really 5KHz?

Maybe you can downsample the signal and run DASYLab at a slower rate

[dnlwthrn]

That's a good point, Tom.  The problem I'm getting seems to be that the hardware can't respond fast enough to duplicate the signal.  I just ran a test on 10hz and 100hz sine waves, with the driver set at 5khz and DASYLab set at 10khz (was having buffer overrun issues @ 5khz), block size of 1.  In the case of the 100hz wave, the output was a stepped waveform that took ~35ms to complete the first half, rather than the 5ms it should have been.  I can attach an data file if you want to look at it.  

The data signal I'm trying to duplicate is around 800hz at its fastest, but changes rate partway through (so I can't use a standard function generator to duplicate it).   The fact that I can't get the Analog Output to mimic a 100hz signal is what has me scratching my head.

CJ, I'll be calling you in a while...  

[TomRizzo]

When you talk to CJ, don't forget to ask her about DAQ options with MMC because they do have board that could perfomr at that speed.

[dnlwthrn]

Well, after a chat with CJ, we got things squared away.  I'm using the "soundboard" driver to play back the signal.  When it didn't work the first time I was a little puzzled... then I realized I needed to unmute the audio on my computer!

[EB_75]

Hello,

I have a similar situation with a DAC 9269.

I acquire with a 9229 a 50Hz sinus waveform (F = 10khz and BS = 10000) using ASCII format. The file is correct, I can draw the curve under Excel.

I try to output these datas using File read module.

The curve is all but the sinus 😞

File read configuration is as follow :

Procedure : use gloal sampling rate is grey.I can't change it

synchronisation : dasylab

Ascii file option : evaluate time (s)

Someone guess what happen ?

Thanks a lot.