can you set the voltage range of NI 9264%3F

[dav2010]

Hi,

I was looking at the NI 9264 and it lists "MAXIMUM OUTPUT RANGE +/-10.65V"   At 16 bit resolution, I believe this means the smallest step is ~0.31mV.  If I want a smaller increment, is it possible to choose the actual output range to be smaller than the MAXIMUM, or is this a default that cannot be changed?

Secondly, it lists the device as 25Ks/s/ch output rate.  Does this mean that if all 16 channels were connected and outputting at their maximum rate, the module would be outputting 16 * 25000 signals per second?

Thanks,

Dave

[johnsold]

Dave,

Read the document carefully.

It specifies "Simultaneous Sampling." That means that you can drive all 16 channels at 25 kS/s as you calculated.  Note that the Update time specification (page 6) in ine chassis is slower than 25 kS/s and is marginal in other chassis. You may need to be very careful with the size and timing of data writes to the device to achieve the maximum rate.

It also has only one range, the +/-10.5 V (nominal) range.  Again you are correct that the resolution is ~0.3 mV.  If your desired output signal varies much more slowly than the 12. kHz Nyquist rate, you might be able to get better resolution with the PWM/dither method.  Basically this involves toggling the least significant bit on and off with a duty cycle proportional to the fraction of the resolution you want.  The technique was presented at NI Week several years ago.

Lynn