Advantech PCI-1710 - Manual (Page 52)

48 PCI-1710/1710HG User's Manual
5.4 D/A Calibration
In a way similar to the ADCAL.EXE program, the DACAL.EXE
program leads you through the whole D/A calibration procedure.
You can either use the on-board -5 V (-10 V) internal reference
voltage or use an external reference. If you use an external reference,
connect a reference voltage within the range ±10 V to the reference
input of the D/A output channel you want to calibrate. Adjust the full
scale (gain) of D/A channel 0 and 1, with VR4 and VR5 respectively.
Note! Using a precision voltmeter to calibrate the D/A
outputs is recommended.
Set the D/A data register to 4095 and adjust VR3 until the D/A output
voltage equals the reference voltage minus 1 LSB, but with the
opposite sign. For example, if V
ref
is -5 V, then V
out
should be +4.9959
V. If V
ref
is -10 V, V
out
should be +9.9918 V.
A/D code Mapping Voltage
Hex. Dec. Bipolar ± 5V Unipolar 0 to 10V
000h 0 -4.9971V 0V
7FFh 2047 -0.0024V 4.9947V
800h 2048 0V 4.9971V
FFFh 4095 +4.9947V 9.9918V