How make two analog channel with different paremeters using NI USB 6341

[Eric-J]

Unfortunately, this is not possible with your device.

[_Pavel_]

Thank you!

What multifunction data acquisition (DAQ) devices I must buy that realize this function using only one card?

Regards, Pavel

[Eric-J]

If you would like to acquire data from two different channels at the same time, you can use a second Create Virtual Channel VI right after the first and use the same task wire. This will allow you to have two different AI channels with different settings.

[_Pavel_]

Hello!

If you make Create Virtual Channel VI "Dev1/ai0", and than connect this with Create Virtual Channel VI "Dev1/ai1" you can configure only min/max voltage on this channels, but you can't configure different clock for this devises. In my first post you can download my example-code and check it.

Regards, Pavel

[johnsold]

Pavel,

Most DAQ cards have only one timing engine for A/D conversions, regardless of how many analog channels they have. On those cards all channels must be sampled at the same rate.

The easiest option: Sample both channels at the higher of the two rates. Then reduce the effective sampling rate on the lower channel in software.  This can be done by discarding samples, averaging groups of samples, or using the Resampling VIs.

Lynn

[_Pavel_]

Hello!

This is acceptable when the sampling rate is constant for the different channels/ However, as shown in my example, I need to realize that one frequency was adjustable.

Pavel

[johnsold]

Pavel,

To have independent sample frequencies for two AI channels, you need to have a DAQ device which has independent A/D converters and independent timing sources for the converters.  I do not know if NI makes such a device. It will almost certainly be less expensive to use two devices.  A second USB-6341 should allow you to do what you want.

Lynn