D/A, A/D Calibration; D/A Calibration Procedure; A/D Calibration Procedures - Advantech PCM-3718 Series User Manual

9.2 D/A, A/D Calibration

Regular and accurate calibration procedures ensure maximal accuracy.
The CALB.EXE calibration program leads you through D/A and A/D off-
set and gain adjustment procedure. The basic steps are outlined below:

9.2.1 D/A Calibration Procedure

Please prepare a multimeter before you implement the D/A calibration.
Connect it to D/A output (pin19 on connector P1)
D/A calibration procedures (PCM-3718HO only)
1. Press the Down button to select the code to 0 and adjust VR6 until
the D/A voltage is 0V
2. Press Up button to set the code to 4095 and adjust VR5 until the D/
A voltage is 5V
3. Repeat step1 and step2, adjusting VR5 and VR6 until the D/A volt-
age is exactly 0 V and 5 V.
4. Connect P1 pin19 as the external DC voltage source to P1 pin1 if
the A/D channel is going to be calibrated.

9.2.2 A/D Calibration Procedures

Connect an external DC voltage source with value of 0.5 LSB to A/D
Channel 0 (pin 1 on connector P1).
1. Adjust VR2 until the output from the card's A/D converter flickers
between 0 and 1.
2. Connect an external DC voltage source with a value of 4094.5 LSB
to A/D channel 0.
3. Adjust VR1 until the A/D reading flickers between 4094 and 4095
4. Repeat steps 2 to step4, adjusting VR1 and VR2
5. Select unipolar input configuration. Connect an external DC volt-
age source with a value of 6. 0.5 LSB to A/D channel 0. Adjust
VR3 until the reading of the A/D flickers between 0 and 1.
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67 Chapter 9