MCC DT9829-8 and MCC USB-2408-2AO sampling rate clarification

[ailiff]

I would like some clarification on two of your DAQ products.

My questions are for both the MCC DT9829-8 and MCC USB-2408-2AO.

Do these models sample the channels sequentially or simultaneously? Additionally, the listed sampling rate for the DT9829-8 is 960 S/s and 1 kS/s for the USB-2408-2AO. Are these rating with with all channels active or just one channel?

Thank you for your support!

-Andy

[Fausto]

Hello @ailiff.

The DT9829-8 samples the analog input channels at a maximum aggregate rate of 960 Hz.  The analog input channels are multiplexed into the A/D; not simultaneous.  The per channel sampling rate is the specified rate (up to 960 Hz) divided by the number of selected channels.

The MCC USB-2408-2AO samples the analog input channels through a multiplexer as well prior to reaching the A/D, also not simultaneous.  Please reference the specifications section in the user's guide.  If you intend to use thermocouples on the input channels, then as explained in the user's guide, the data rate should be set to 60 Hz in InstaCal.  Therefore, decreasing the maximum sampling rate to 57.78 Hz divided by the number of channels selected. (Reference Table 11 in the user's guide.)

Do you have either device or looking to use one in your application?

Regards,

Fausto

[ailiff]

Fausto,

Firstly, I apologize for my duplicate post. I am new to forum etiquette and really just needed this question answered quickly.

Secondly, I appreciate the clarification.

We are looking to use one of these products in an application to sample data from up to 10 load cells.

That being said, I would like to get clarification on something else related to data acquisition and these products.

If we were to use the USB-2408 with 10 SE analog inputs active would that mean that the fastest possible sample rate for each channel is ~100 S/s?

Thanks!

-Andy 

[Fausto]

Andy,

Please share the datasheet of your load cells.  Will you be supplying an external power supply to the load cell or expecting the data acq device to provide an excitation power?  What is the maximum sampling rate per channel required for your application and is simultaneous channel capture a requirement?

A differential wiring configuration for acquisition is typically the norm with load cells.

Something to know... 

Regards,

Fausto

 

[ailiff]

We are supplying external power and running the load cells through signal conditioners (0-5 V out) before entering the DAQ. This is why we are going with a SE implementation.

We need a minimum sampling rate of 100 Hz. Simultaneous sampling would be the preferred method.

[Fausto]

Consider the MCC USB-1608GX with a 500 kS/s maximum aggregate sampling rate instead.  If you set the sample rate to 100 kS/s, then for 10 analog input channels, the time between adjacent (channel) acquisition is 0.01 milliseconds.  Is that acceptable for your simultaneous requirement?

[ailiff]

The 0.01 msec may be sufficient. However, we need a 24-bit DAQ.

[Fausto]

Hello @ailiff.

The USB-2408-2AO has a 24-bit A/D, but does not support simultaneous captures. 

A higher-end option is the DT9857E-16-xAO (SKU: 6069-410-039).  The DT9857E-16-xAO supports simultaneous captures with individual 24-bit A/D's, 16 analog input channels, and a maximum sampling rate greater than your requirement.  

Regards,

Fausto