Collecting Square Pulse from SRS DG535

[Vlngrl87]

I would like to collect a square pulse from the SRS DG535 Pulse Generator to see how the timing of the pulse generator compares to that of our new PCI 6115.  I've connected the AB output of the pulse generator to the DAQ card, but I can't seem to get the settings right so that the pulse shows up as a square wave on a waveform graph.  I have been using the DAQ assistant in order to acquire the data, and the spacing seen does appear to match with the pulse generator (B = T+0.1).  I've tried to download the Instrumentation drivers for the DG535, but I don't know how to make them work to show this pulse. Currently, it looks like: http://picasaweb.google.com/ekloppen/Labview#5254238872506375426.

Thanks for your help.

[Wallace_F]

Hi VIngrl87,

The AB output of the SRS DG535 pulse generator is a BNC connector, but how are you physically connecting this output to the PCI-6115? Are you using a National Instruments BNC-21XX connector block to connect the output of the pulse generator to the input of the DAQ board? Also, what are the output parameters of the pulse generator, and what are the input parameters for you measurement task in LabVIEW?  In other words, how do you have the DAQ assistant configured?

Best wishes,

Wallace F.

[Vlngrl87]

Wallace,

Yes, I am using a BNC-2110 connector block. The output of the pulse generator is a load with 50 ohm impedance, an amplitude of 0.72 volts, and an offset of 0.05 volts.  I've been trying various things for the DAQ assistant.  Rigth now, I have the signal imput range with a max of 0.72 volts and a min of zero volts.  The terminal configuration is pseudodifferential.  I've been running it in continuous mode with differing amounts of samples and rates.  The device is in AC coupling mode with no trigger and an internal sample clock.

Thanks.

[Vlngrl87]

Also, initially, I chose to acquire voltage analog input through channel ai0.

[Wallace_F]

Hello VIngrI87,

I have a few more questions.  What are the input task parameters that you have set in your DAQ Assistant, such as sampling rate, samples to read,  signal input range max and min, and terminal configuration?  Does the terminal configuration setting in the DAQ Assistant match the terminal configuration selector switch (FS or GS) of the BNC-2110? Have

you tried looking at the signal in ai0 in a test panel in Measurement & Automation Explorer?  If so, is it the same as the result when acquiring the signal with a DAQ Assistant?

Regards,

Wallace F.

[Vlngrl87]

Wallace,

I've varied the sample number from 5 - 5M, and the rate from 1 - 1M Hz.  I have the signal imput rate set to have a max at 0.72 volts and a min at 0 volts. The terminal configuration is pseudodifferential, and I've tried both settings for the terminal configuration selector switch fo the BNC-2110.  I do get the same result when acquiring the signal with Measurement & Automation Explorer

Thanks. 

[Wallace_F]

Hello,

There are a couple of additional things that you should try in your efforts to troubleshoot your analog input with the PCI-6115. First, I recommend trying to acquire the signal on different analog input channels, if you haven't already.  I also recommend trying to acquire different signals from different sources.  Another thing to do is verify that signal coming from the SRS DG535 using some other measuring device, such as an oscilloscope if you have one available.  The last thing I would recommend is to generate an analog signal with the PCI-5115 using test panels in Measurement & Automation Explorer, and then acquiring those signals using the DAQ Assistant express VI in LabVIEW.  Also, what version of the NI-DAQmx driver do you currently have installed on your computer?  You can verify the version of DAQmx by expanding the software section of the configuration tree in Measurement & Automation Explorer.

Regards,

Wallace F.