B&B Electronics PCI-1711 - Manual - Manual (Page 111)

Appendix E
– 103 – PCI-1710 series User’s Manual Advantech Co., Ltd.
www.advantech.com
E.2 D/A Calibration (for PCI-1716 only)
You can select an on-board +5V or +10V internal reference voltage or
an external voltage as your analog output reference voltage. If you use
an external reference, connect the reference voltage within the ±10V
range to the reference input of the D/A output channel you want to
calibrate. Then adjust the gain value, unipolar offset voltage, bipolar
offset voltage, respectively, of D/A channels 0 and 1 with the Calibra-
tion Command and Data register (BASE+18).
Note:
✎ Using a precision voltmeter to calibrate the D/A outputs is
recommended.
The auto-calibration program AutoCali.EXE helps you finish the D/A
calibration procedure automatically. In order to get the maximum
possible accuracy of the D/A channels, you need to calibrate the A/D
channels first. Although the procedure is not necessary, the following
calibration steps are provided below for your reference in case you
want to implement the calibration yourself:
1. Writing 0x0400, 0x0500, 0x0600, 0x0700, 0x0800, 0x0900, 0x0A00 and
0x0B00 sequentially to Calibration Command and Data register
(BASE+18). Next, to set PCI-1716/1716L to AI software trigger and
calibration mode. After that, to set the A/D channel to correspond-
ing D/A channel. That means connected A/D channel 4 to D/A
channel 0, connected A/D channel 6 to D/A channel 1.
2. Adjust GAIN 10V calibration. First, writing any value to BASE+9 to
clear FIFO. Then to set the A/D range as 0 V to 10 V, and to set the
D/A range as 0 V to 10 V. Next, writing 0xFFFF to corresponding D/
A registers (BASE+10 and BASE+12).
3. Writing the value from 0x0400 to 0x04FF sequentially to Calibra-
tion Command and Data register (BASE+18), and get each
bipolar range’s data by software trigger A/D method. Be noted that
to repeat this procedure 1000 times then to average those data for
each value. After that, to see whether the average data is close to
65534.6. If so, to go to next step. Otherwise, you must change the
value and repeat all the procedure in this step again until the
average data close to 65534.6.