Advantech PCI-1710 - Manual (Page 51)

Chapter 5 Calibration 47
The following list shows the function of each VR:
VR Function
VR1 A/D unipolar offset
VR2 A/D bipolar offset
VR3 A/D full scale (gain)
VR4 D/A channel 0 full scale
VR5 D/A channel 1 full scale
5.3 A/D Calibration
Regular and accurate calibration procedures ensure the maximum
possible accuracy. The ADCAL.EXE calibration program leads you
through the whole A/D offset and gain adjustment procedure. The
basic steps are outlined below:
1. Set analog input channel AI0 as single-ended, bipolar, range
±
5 V,
and set AI1 as single-ended, unipolar, range 0 to 10 V.
2. Connect a DC voltage source with value equal to 0.5 LSB
(-4.9959 V) to AI0.
3. Adjust VR2 until the output codes from the card's AI0 flickers
between 0 and 1.
4. Connect a DC voltage source with a value of 4094.5 LSB (4.9953
V) to AI0.
5. Adjust VR3 until the output codes from the card's AI0 flickers
between 4094 and 4095.
6. Repeat step 2 to step 5, adjusting VR2 and VR3.
7. Connect a DC voltage source with value equal to 0.5 LSB (1.22
mV) to AI1.
8. Adjust VR1 until the output codes from the card's AI1 flickers
between 0 and 1.