ADC Range
Input voltage range over which the ADC will convert input voltages to digital values. Voltages outside of the range will clamp at the extremes, which are –2048 or +2047 (7330/40) and –32,768 to +32,767 (7350) for the –5 to +5 V and –10 to +10 V ranges, and 0 or 4,096 (7330/40) and 0 or +65,535 (7350) for the 0 to +5 V and 0 to +10 V ranges. You can choose from the following ranges:
| Binary Values | ||
|---|---|---|
| Range Values | 7350 | 7330/40 |
| 0 to 5 | 0 to +65,535 |
0 to +4,095 |
| –5 to +5 | –32,768 to +32,767 |
–2,048 to +2,047 |
| 0 to +10 | 0 to +65,535 |
0 to +4,095 |
| –10 to +10 (default) | –32,768 to +32,767 | –2,048 to +2,047 |
If you know that the input voltage falls within a more restrictive range, you can effectively increase the resolution of the measurements by selecting an appropriate range from the previous list.
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Note With the 7350 motion controller, changing the range of an ADC changes all other ADCs to the same range. Other NI motion controllers can set the range independent of other ADCs. |
For example, if you are using a 7340 motion controller, the input signal ranges from –3 to +3 V, and you select the –5 to +5 V range, the 4,096 discreet values for the ADC is 2.44 mV apart instead of the 4.88 mV apart when using the –10 to +10 V range. If you are using a 7350 motion controller, the input signal ranges from –3 to +3 V, and you select the –5 to +5 V range, the 65,536 discrete values for the ADC is 152 µV apart instead of the 305 µV apart when using the –10 to +10 V range.
ADC ranges cannot be changed on any ADC while an axis that is using analog feedback is enabled. You must first disable the axis using analog feedback, then change the range.