Can input range limit be modified while AI Read running

[gastonkgn]

Is it possible to increase the precision on the PC-6052E by having an auto detection of the input signal and reducing the input range to increase the precision of the A/D conversion?

We are continuously acquiring the signal from DAQ Analog Input. Say input signal (range -10V to 10V) came in at 1V, can we reset the input range limit to (0to+1V) to increase the precision to 15.3microV instead of 305microV for (-10to+10V). i.e. To have an auto-detection mode for the signal and readjust the input range accordingly.

Gaston

[L Aguila]

Hello Gaston,

Based on my experience. I think this is not possible, because in order to modify the Input Limits, which also affect the Gain of the ADC, you must use first the AI Config.VI in the flow of your program. Thus, in order to reconfigure the Input Limits, you should use again the AI Config.VI which means you must stop the acquisition for reconfiguring the Input Limits.

I guess the best thing to do is to know more less what range of signal you are expecting and set the lowest permissible value.

I hope this helps.

L Aguila
Applications Engineer
National Instruments

[Filipe A.]

Hello;

You can do that, but, you will need to stop and reconfigure the Analog Input task at each time. That might cause the application to loose data (depending on the speed of the application).

It's not possible to reconfigure the acquisition parameters on the fly.

Hope this helps.
Filipe A.
Applications Engineer
National Instruments

[SteveP]

Configure the acquisition to sample the same channel multiple times, each at a different gain. Use a short (10 or 100 usec ?) interchannel delay so these samples are taken close together in time to each other. Then in software examine the data from all the gain setting to determine the highest gain that did not saturate. If the gains are well matched (a signal of 0.5 V gives the same data value on a 1V input range as on a 10 V range), then the values can be combined into one final data array. If not, then keep a running separate array for each gain and only use the array from the gain which did not saturate over all data values.