Kontron PCI-AOB16/12, User Manual

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Introduction 8-3 PCI-AOB8/12 (16/12) User’s Guide
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Introduction
Periodic calibration of the PCI-AOB8/12 (16/12) cards is recommended if they are used in
extreme environmental conditions. The card uses very stable components but high-low
temperature cycles might result in slight analog output errors.
This card is calibrated by software using the following formula:
Y= (4096 -a - b)/4096) * X + b
To calibrate the card, run the calibration program and follow the screen prompts. No attempt at
calibration should be made in noisy locations or with a noisy calibration setup.
The calibration program stores various data to the card to facilitate calibrating the data output
in a run-time environment. The data collected during calibration is stored in an EEPROM located
at the second of the I/O base addresses assigned to the device (BaseAddresses[3] in the
PCI_COMMON_CONFIG structure). The EEPROM contains two values per channel per range. The
ZERO (or OFFSET) and the SPAN calibration constants are stored (a and b from the equation
above) for each channel at each possible range (0-6). These constants are used during normal
operation to calibrate the output data in real-time. Refer to the samples provided on disk for an
example of using this data.