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J605 APCI-ADADIO
Utility Disk
A demonstration program has been provided on the utility disk ADADIO.EXE.
This can be used to aid calibration and as source code is provided it will help demonstrate the
method used for accessing devices.
ADADIO.EXE
This program will display the ADC inputs, scroll an active bit along the digital I/O and allows setting
of the DACs. These will work with standard link settings. Decrementing counter/timer counts and
incrementing interrupt counts are also displayed, but a link must be fitted between pins 9 and 10 on
PL3.
ADADIO.INI
This is a text file which is used by the ADADIO program to select the number of channels, ADC and
DAC ranges etc. This file can be edited to reflect any changes in the board settings.
Calibration
Calibrating the ADC
In order to calibrate the ADC it is necessary to use a precision digital voltmeter (DVM) with at least
5 digit resolution and a high stability low noise DC signal source. During calibration it is necessary
to continually read and display the ADC data. A program ADADIO.EXE has been provided on the
utility disk to enable this.
Two trim adjusters, VR7 and VR1 , are provided for trimming the zero offset and gain respectively.
These trims are for fine-adjusting the standard ranges.
Unipolar Calibration
Set the necessary links for unipolar operation and the required voltage range. Run the ADADIO.EXE
program.
Zero Offset Adjust
1) Set the input voltage to 0.0000V.
2) Adjust VR7 to give 000 to 001 hex.
Full Scale Gain Adjust
1) Set the input voltage to full scale minus 1 LSB
+4.9985 for the 5V range.
+9.9975 for the 10V range.
2)Adjust VR1 to give FFE to FFF.
Bipolar Calibration
Set the necessary links for bipolar operation and the required voltage range. Run the ADADIO.EXE
program.
Bipolar Offset Adjust
1) Set the input voltage to full scale negative plus 1 LSB
-4.9975 for the 5V range.
-9.9950 for the 10V range.
2) Adjust VR7 to give 000 to 001 hex.
