Konica Minolta PCI-1712 사용자 설명서

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6.2 A/D Calibration

Regular and proper calibration procedures ensure the maximum
possible accuracy. It is easy  to complete the A/D calibration proce-
dure automatically (i.e. through software calibration) by executing the
A/D calibration program  AutoCali.  Therefore, it is not necessary to
adjust the hardware settings of the PCI-1712/1712L.  However, the
following calibration  steps are also provided for your reference in case
manual calibration is needed:

1. Adjust VR1 until the reference voltage on TP5 has reached

+5.0000 V.

2. Set PCI-1712 to calibration mode, which will configure AI2 to +5

V, and AI0 to 0 V. (Write “1”  in AI0_CAL at the register address

BASE+6 bif7).

3. Adjust the PGA offset voltage. First, set the analog input voltage

range of AI0 to ±10V. Adjust the PGA offset register (BASE+2C),

and acquire a value from AI0 in single value acquisition mode.

Then switch the analog voltage range to ±1.25V to repeat the

operation in this step again to acquire a value from AI0. Repeat

this cycle  several times. Meanwhile, adjust the PGA offset

voltage until the AI0’s values become the same for both the

analog input range ±10 V and  ±1.25 V.

4. Adjust the gain value of the PGA. First, set the analog input

voltage range of AI2 between 0 and 5V. Adjust the gain register

(Base+2C), and then acquire the value for AI2 from single value

acquisition mode. Adjust the gain value of the PGA until the

subsequent AI2’s values converge within the   

Ox0ffe

 to

Ox0fff

  range.

5. Adjust the bipolar offset voltage. First, set the analog input

range within ±2.5 V. Adjust the bipolar offset register (Base+2C),

and then acquire the code from AI0 from single value acquisition

mode. Adjust the bipolar offset voltage until the AI0’s code

flickers around 

Ox0800

.

6. Adjust unipolar offset voltage. First, set the analog input range

within 0 and 5 V. Adjust the unipolar offset register (Base+2C),

and then acquire the code for AI0 from single value acquisition