Chapter 5
PCI-1711/1731 User’s Manual
Advantech Co., Ltd.
www.advantech.com
– 30 –
VR
Function
VR1
A/D bipolar offset adjustment
VR2
A/D full scale (gain) adjustment
VR3
D/A channel 0 full scale adjustment
VR4
D/A channel 1 full scale adjustment
Fig. 5-2 PCI-1731 VR assignment
The following list shows the function of each VR :
5.2 A/D Calibration
Regular and accurate calibration procedures ensure the maximum
possible accuracy. The A/D calibration program ADCAL.EXE leads
you through the whole A/D offset and gain adjustment procedure. The
basic steps are outlined below:
1. Connect a DC voltage source of +9.995 V to AI0.
2. Connect AGND to AI1, AI2, AI3, AI4 and AI5.
3. Run the ADCAL.EXE program.
4. Adjust VR2 until the output codes from the card’s AI0 are
focused on FFE (at least 70%), and adjust VR1 until the output
codes from the card’s AI1, AI2, AI3, AI4 and AI5 are focused on
7FF (at least 70%).
5. Press the SPACE key to finish A/D calibration.
5.3 D/A Calibration
The D/A calibration program DACAL.EXE leads you through the
whole D/A calibration procedure.
You can select the 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 a reference voltage within the range
V R1 V R2
