Advantech MIC-3716, Manual

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7. Writing the value from 0x0600 to 0x06FF sequentially to the
Calibration Command and Data register (BASE+18), and get
each bipolar range’s data by the software trigger A/D method.
Repeat this procedure 1000 times to average those data for each
value . After that, see whether the discrepancy is less then 0.4 LSB.
If so, go to the next step. Otherwise, you must change the value
and repeat the whole procedure in this step again until the
discrepancy is less then 0.4 LSB.
8. Adjust UNIPOLAR offset calibration. First, write any value to
BASE+9 to clear FIFO. Then set the A/D range as -5 V to +5 V,
and set the D/A range as 0 V to 5 V. Next, write 0x8000 to the
corresponding D/A register s (BASE+10 and BASE+12).
9. Write the value from 0x0600 to 0x06FF sequentially to the
Calibration Command and Data register (BASE+18), and get
each bipolar range’s data by the software trigger A/D method.
Repeat this procedure 1000 times then average those data for each
value . After that, see whether the average data is close to 32767.5.
If so, go to the next step. Otherwise, you must change the value
and repeat the whole procedure in this step again until the average
data close is to 32767.5.
10. Repeat steps 2 to 9 several times.