User`s guide

68  Calibration & Utilities
6.2 VR Assignment
There are five variable resistors (VR) on the ACL-8316/12 board to allow you
making accurate adjustment on A/D and D/A channels. The function of each
VR is specified as Table 6.1.
VR1 A/D bipolar offset adjustment
VR2 A/D full scale adjustment
VR3 D/A channel 1 full scale adjustment
VR4 D/A channel 1 offset adjustment
VR5 D/A channel 2 full scale adjustment
VR6 D/A channel 2 offset adjustment
VR7 A/D programmable amplifier offset adjustment
Table 6.1 Function of VRs
6.3 A/D Adjustment
1. Set the analog input range as: +/- 10V, i.e. the gain = 1
2. Short the A/D channel 0 ( pin 1 of CN3) to ground(GND), and connect the
TP1(+) and TP2(-) with your DVM. Trim the variable resister VR7 to
obtain a value as close as possible to 0V.
3. Applied a +0V input signal to A/D channel 0, and trim the VR1 to obtain
reading between 0 to 1.
4. Applied a +10V input signal to A/D channel 1, and trim the VR2 to obtain
reading between 2046~2047 (8312) or 32766~32767 (8316).
5. Repeat step 3 and step 4, adjust VR2 and VR1.
6.4 D/A Adjustment
6.4.1 DA Channel 1 Calibration
1. Set JP5 to BI1 (Bipolar for DA Channel 1).
2. Connect VDM (+) to CN3.AO1 pin-30 and VDM(-) to CN3.GND pin-29.
3. Set DA1 output to 0x8000
4. Trim the variable resister VR4 to obtain -10.005V reading in the DVM.
5. Set DA1 output to 0x7FF0
6. Trim the variable resister VR3 to obtain +10V reading in the DVM.