ADLINK PCI-9524 - Manual (Page 83)

Operation Theory 67
ADLINK Technology Inc. PCI-9524
Copyright 2008 User’s Manual
4.3 D/A Conversion
There are two single-ended channels of 16-bit analog outputs
available on PCI-9524. They support software polling to update
the output status. Therefore, the update rate is fully controlled by
software timing.
PCI-9524 supports a maximum ±10V voltage output. Table 4-7
illustrates the relationship between 2's Complement coded binary
and output voltage.
Table 4-7: Bipolar output code table
Binary Code (Hex) Analog Output
0x7FFF 10V * (65535/65536)
0x0001 10V * (1/65536)
0x0000 0V
0xFFFF -10V * (1/65536)
0x8000 -10V
The D/A is designed to have 0.5% over-range used for internal
digital calibration. Therefore, there are approximately 327 codes
being traded at the extreme ends of the D/A transfer function.
While the transfer function remains linear after calibration, code
mapping is required to have calibrated output voltages. Using the
supplied API and software routines will do the required mapping
for you; the valid input binary code range remains unchanged,
from 0x0000 to 0xFFFF.
4.4 Isolated Encoder Input Channels
There are three opto-isolated differential encoder input channels
in PCI-924 accepting both single-end and differential encoder sig-
nals, including NPN sink drivers, PNP source drivers, push-pull
drivers, and differential line drivers.