DAQmx Analog Output Maximum Multichannel Rate

[David_Porras]

I'm building a flexible application that should adapt to different DAQ Devices (even to future DAQ Devices), so we need to find a way to get the Analog Output Maximum Multichannel Sample Rate value somehow. I know that this specification it's stated on the Device Specification, but the DAQ Device could change anytime for a few years, so we need to find a way to check this automatically. There's a DAQmx Property Node that returns the AI Maximum Multichannel Rate:

Is it something similar to get or calculate the same spec. for analog outputs?

Thanks in advance for your support.

[Tepig]

Hi, I found following property and looked returning valid value.

My USB-6361 (2.86 MS/s) returned "2.85714M" (Umm... there was small diff).

[David_Porras]

Thank you Emboar,

That value is the maximum rate for an AO Single Channel, but when you use more than one AO, the sample rate may decay if the DAQ device multiplexes the AO. That’s why I’m looking for a way to get the AO Maximum Multichannel Rate, for analog input tasks it’s a piece of cake as there's a DAQmx Property Node that returns the AI Maximum Multichannel Rate and there’s also another one that returns the AI Maximum Rate (single channel), but for Analog Output I can only find a property mode that returns the AO Maximum Rate (single channel), but not the AO Maximum Multichannel Rate.

I’m expecting that maybe there’s a formula to calculate that value, or even better, a property node.

[Kevin_Price]

I couldn't find such a property node either and I'm pretty sure there isn't a *formula* as I've seen devices whose max AO rate was *independent* of the # channels, and others where the relationship was, well, not purely formulaic.

Out of curiousity, have you explored the results from the AI max multichannel rate?   Because it seems it would mainly be a factor for multiplexing devices, in which case it would be heavily dependent on the # AI channels in the task.  In other words, the max multichannel rate would have to correspond to the minimum # channels that could still be "multichannel", i.e., 2.

Or does that property *actually* return the max rate available for the *max* # AI channels?   And even then, with some devices the max # channels depends on single-ended vs differential wiring.

In short, it seems that an accurate response from this query would require more inputs such as # channels and wiring config.  I'm wondering whether the AI max multichannel rate property is *actually* giving you the info you want and need.  (I haven't explored it this way across lots of hardware and am not near any now to check it out.)

-Kevin P

[Tepig]

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That value is the maximum rate for an AO Single Channel, but when you use more than one AO, the sample rate may decay if the DAQ device multiplexes the AO. That’s why I’m looking for a way to get the AO Maximum Multichannel Rate

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I don't know it would be a problem there are multiple channels in a task. As 1st step, read Max rate at single channel and then, begin your actual code. If it doesn't help you, I have no idea how to accomplish your request.