B&B Electronics PCI-1711 - Manual - Manual (Page 48)

Chapter 5
– 40 –
PCI-1710 series User’s Manual
Advantech Co., Ltd.
www.advantech.com
Note:
✎ Using a precision voltmeter to calibrate the D/A outputs is
recommended.
Set the D/A data register to 4095 and adjust VR3 until the D/A output
voltage equals the reference voltage minus 1 LSB, but with the
opposite sign. For example, if V ref is -5 V, then V out should be
+4.9959 V. If V ref is -10 V, V out should be +9.9918 V.
Self A/D Calibration
Under many conditions, it is difficult to find a good enough DC
voltage source for A/D calibration. There is a simple method to solve
this problem. First, you should calibrate D/A channel 0, DA0_OUT,
with internal reference -5 V, and D/A channel 1, DA1_OUT, with
reference -10 V.
Then, run the ADCAL.EXE program to finish the self-A/D calibration
procedure.
1. Set AI0 as differential, bipolar, range ±5 V and AI2 as differential,
unipolar, range 0 to 10 V.
2. Connect DA0_OUT with codes equal to 4095 LSB (4.9959 V) to AI
0. Notice that the polarity of AI0 should be connected with reverse
polarity (i.e. D/A + to A/D -, D/A - to A/D +).
3. Adjust VR2 until the output codes from the card’s AI0 flicker
between 0 and 1.
4. Connect DA0_OUT with codes equal to 4095 LSB (4.9959 V) to
AI0.
5. Adjust VR3 until the output codes from the card’s AI0 flickers
between 4094 and 4095.
6. Repeat steps 2 through 5, adjusting VR2 and VR3.
7. Connect DA1_OUT with codes equal to 1 LSB (2.44 mV) to AI2.
8. Adjust VR1 until the output codes from the card’s AI1 flicker
between 0 and 1.
9. Finish ADCAL.EXE.