National Instruments VXI-MIO Series - Manual (Page 39)

Chapter 3 Hardware Overview
VXI-MIO Series User Manual 3-10  National Instruments Corporation
Analog Output
♦
VXI-MIO-64E-1
This module supplies two channels of analog output voltage at the
I/O connector. The reference and range for the analog output
circuitry is software-selectable. The reference can be either internal
or external, whereas the range can be either bipolar or unipolar.
♦
VXI-MIO-64XE-10
This module supplies two channels of analog output voltage at the
I/O connector. The range is bipolar or unipolar.
Analog Output Reference Selection
♦
VXI-MIO-64E-1
You can connect each D/A converter (DAC) to this module’s
internal reference of 10 V or to the external reference signal
connected to the external reference (EXTREF) pin on the I/O
connector. This signal applied to EXTREF should be between -10
and +10 V. You do not need to configure both channels for the
same mode.
Analog Output Polarity Selection
Selecting a bipolar range for a particular DAC means that any data
written to that DAC will be interpreted as two’s complement format. In
two’s complement mode, data values written to the analog output
channel can be either positive or negative. If you select unipolar range,
data is interpreted in straight binary format. In straight binary mode,
data values written to the analog output channel range must be positive.
♦
VXI-MIO-64E-1
You can configure each analog output channel for either unipolar
or bipolar output. A unipolar configuration has a range of 0 to V
ref
at the analog output. A bipolar configuration has a range of -V
ref
to
+V
ref
at the analog output. V
ref
is the voltage reference used by
the DACs in the analog output circuitry and can be either the
+10 V onboard reference or an externally supplied reference
between -10 and +10 V. You do not need to configure both
channels for the same range.