Chapter 2
Installing and Configuring the DAQCard-1200
DAQCard-1200 User Manual
2-6
ni.com
Analog Output Polarity
The DAQCard-1200 has two channels of AO voltage at the front panel I/O
connector. You can configure each AO channel for either unipolar or
bipolar output. A unipolar configuration has a range of 0 to 10 V at the
analog output. A bipolar configuration has a range of –5 to +5 V at the
analog output. If you select a bipolar range for a D/A conversion, the
two’s complement coding mode is selected. In this mode, data values
written to the AO channel range from F800 hex (–2,048 decimal) to 7FF
hex (2,047 decimal). If you select a unipolar range, you are selecting the
straight binary coding. In this mode, data values written to the AO channel
range from 0 to FFF hex (4,095 decimal).
Configuring Digital I/O
The DAQCard-1200 uses the MSM82C55 programmable peripheral
interface (PPI). This chip provides 24 digital lines in the form of
three ports—A, B, and C. On power up, all three ports reset to
high-impedance inputs. For information about configuring the
MSM82C55, Refer to the
Analog Input Timing Connections
section of
Chapter 3,
Caution
The DAQCard-1200 DIO lines are not pulled up or pulled down. If you are using
these lines as digital outputs, add 10 k
Ω
resistors to +5 V or DGND (depending on your
application) to the DIO line(s) you are using.
Configuring Counters
You can use the MSM82C53A counter/timers for general-purpose timing
applications, such as pulse and square wave generation, event counting,
and pulse-width, time-lapse, and frequency measurements. For information
about configuring the MSM82C53A, refer to the
section of Chapter 3,
.
