Need help to use LabVIEW to operate a Digital-Analog Convertor (DAC) board (16 bits, SPI interface, 4 channels))

[EEACT23]

Hello everyone,

I'm currently facing an issue and would appreciate your help. I am attempting to update a LabVIEW program to work with a new DAC. Here is some information for reference:

• The old DAC is DC 752 A-B, and the new one is DC2376 A-A. They are from the same manufacturer and were claimed to be "pretty similar". I have attached both datasheets for reference.
• The DAC board and LabVIEW program are operated and communicated through the NI PCI-6224 -> NI CB-68LPR -> 3 pins on the DAC board (SDI, SCK, CS/LD).

Here is my approach:

• I changed the address code from 0, 2, 4, 6 to 0, 1, 2, 3 for the four outputs on the DAC. (Red circle in the Figure 1)
• I changed the command code from 6, 7 to 6, 0 (Blue circle in the Figure 1).
• In DC 752 A-B, command 6 & 7 are "Write to B1 Span DAC n, Update B1 -> B2 DAC n" and "Write to B1 Code DAC n, Update B1 -> B2 DAC n."
• In DC 2376 A-A, command 6 & 0 are "Write Span to n" and "Write Code to n."
• The problem is that there is no single command that does both write code/span and update in new DAC board (DC 2376 A-A). Therefore, I added an update command by adding a flat sequence case to the original code and adding an update command after each write/span operation (Red circle in the Figure 2). (FYI, the Figure 2 is the block diagram of the subVI - Drive Operate Data in the Figure 1, original code doesn't have flat sequence case and the red circle part)

So far, my approach has not been successful. Can you help me properly implement the "update operation" in the program?"

[santo_13]

Even if one would like to update "your program" they could not because you did not attach a VI rather attached a image and nobody could edit the image into a working VI.

You've attached datasheet of LTC DACs but I don't find it related to "DC 752 A-B" or "DC2376 A-A" audio aplifiers.

BTW, you need to pass the data to the DAQmx VIs and not just to some random indicator and control for the DAQ to generate those signals.

[EEACT23]

Hello santo_13,

Thank you for your response, I appreciate your input.

I did not upload the actual VI due to an agreement I have with the original writer of the application to not share it elsewhere.

The two documents I attached provide information on the main chip of the DACs, which serves as the "heart/brain" of the DAC and determines how the entire DAC operates.

I am very interested in your suggestion to "pass the data to the DAQmx VIs and not just to some random indicator and control for the DAQ to generate those signals." Could you please provide more information on how to implement this and give further insight?

Regarding the figure I attached, the reason I directly linked two clk outputs in the second frame of the flat sequence to the local variable is because I only know how to use local variables to deal with the "two different inputs in in-sequence, one output out" situation due to my limited knowledge of LabVIEW. As you can see, those two outputs are not only indicators but have also been assigned to the connector pane and have been used to transfer data in the part where they were called out in the main VI (circled in red in the figure).

Could you please clarify if the program will not work as I thought (i.e., the subVI keeps outputting while the first and second frames are running) or if the rest of the main VI (the part after the subVI) will only accept output from the second frame, which will only operate after the whole subVI is done?

Thank you,