Serial ADC Read

[awar99]

    Greetings. I am endevouring to read from an Analog Devices serial ADC (AD7872) using LabView and a PCI 6534 card.
Data out of the ADC is valid on the falling edge of the SCLK output of the ADC. What I would like to do is trigger a single read of SDATA on the falling edge of SCLK. Unfortunately, I get an error stating something to the effect that the start trigger type is not supported due to requested timing type. I am having trouble finding examples that are similar to what I am trying to do, so any help with this would be greatly appreciated.

Thank you.

[Ima U]

Hello Awar99,

From my understanding you are using LabVIEW, PCI 6534 to do a single digital read with a start trigger.  I am assuming that you are using DAQmx. 

According to the page 3 of the 6534 Specifications guide, your device does support start triggers.  I checked the device routes in MAX (Measurement and Automation Explorer) and the only signals you can use as a start trigger on your device are RTSI 1 - RTSI 6.  You can find the device routes in MAX.  Open MAX and select "My System">>"Devices and Interfaces">>"NI-DAQmx Devices">>NI PCI-6534.  Next select the "Device Routes" tab. 

A good DAQmx shipping example to start from is called Read Dig Chan-Int Clk-Dig Ref.vi.  You can find it in the DAQmx example finder.  In LabVIEW go to Help and select "Find Examples".  In the browse tab choose "Hardware Input and Output">>"DAQmx">>Digital Measurements>>Read Dig Chan-Int Clk-Dig Ref.vi.  You can modify this VI to do exactly what you want.  For example, you can change the reference trigger to be a start digital edge trigger. 

If this was not helpful then please answer the following questions and post your code. 

1. What is the error code/# and message you receive?
2. What version of LabVIEW are you using?
3. What version of DAQmx are you using?