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Chapter 3 Hardware Overview
©
National Instruments Corporation 3-5 PCI-4451/4452 User Manual
Caution If you exceed the rated input voltages, you can damage the computer and the
connected equipment.
Analog Output
The analog output section of the PCI-4451 device is software-configurable.
You can select different analog output configurations through application
software designed to control the PCI-4451. The following sections describe
in detail each of the analog output categories. The PCI-4451 device has two
channels of analog output voltage at the I/O connector.
Output Mode
The PCI-4451 device uses DIFF outputs. You can configure the outputs as
an SE channel using the BNC-2140 DSA accessory. For more information,
please refer to the BNC-2140 User Manual. In DIFF mode, one line
connects to the positive input of the channel, and the other connects to the
negative input of that same channel. You can connect the differential output
to either SE or DIFF loads, either floating or ground-referenced. However,
grounding the negative output is recommended when driving floating
single-ended loads.
Output Polarity and Output Range
The PCI-4451 device operates in bipolar mode. Bipolar output means that
the output voltage range is between –V
ref
/2 and +V
ref
/2. The PCI-4451 has
a bipolar output range of 20 V (±10 V) for an attenuation of 1.0 (0 dB).
You can program the range settings on a per channel basis so that you can
configure each output channel uniquely. The software-programmable
attenuation on these devices increases their overall flexibility by matching
the output signal ranges to the your application. Table 3-2 shows the overall
output range and precision according to the attenuation used.
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User.book Page 5 Tuesday, April 14, 1998 10:20 AM