Specifications

64
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.
A/D code Mapping Voltage
Hex. Dec. Bipolar ±5V Unipolar 0 to 10V
000h 0 -4.9971 V 0 V
7FFh 2047 -0.0024 V 4.9947 V
800h 2048 0 V 4.9971 V
FFFh 4095 4.9947 V 9.9918 V