User`s guide

54 • Calibration
6.4 A/D Calibration
Since the ACL-8111 provides versatile A/D input ranges, the
calibration on one A/D range may cause a small offset on other
ranges. It is suggested that you calibrate the A/D range which you
need best accuracy.
The procedures of calibration are as follows:
1. Set the analog input range as: +/- 5V, i.e. the gain = 1
2. Short the A/D channel 0 (pin 1 of CN1) to ground (GND), and
connect the TP1 (+) and TP2 (-) with your DVM. Trim the variable
resister VR5 to obtain 0 reading in the DVM.
3. Applied a +5V input signal to A/D channel 0, and trim the VR4 to
obtain reading between 4094~4095.
4. Applied a +0V input signal to A/D channel 0, and trim the VR3 to
obtain reading flickers between 2048~2049.
5. Repeat step 2 and step 3, adjust VR3 and VR4.