Chapter 3
Hardware Overview
PCI-4451/4452/4453/4454 User Manual
3-6
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improves the voltage resolution, but can result in the input signal going out
of range. For best results, match the input range as closely as possible to the
expected range of the input signal.
If you do not choose an appropriate input range, the input signal can be
clipped and introduce large errors that are easily identified in the frequency
spectrum. The PCI-4451/4452 is equipped with overrange detection
circuits in both the analog and digital sections of each input channel. These
circuits determine if an input signal has exceeded the selected input
voltage. Chapter 6,
, provides a more in-depth
explanation of how overranges can occur.
♦
PCI-4453/4454
The PCI-4453/4454 does not feature any range setting capability and is not
equipped with overrange detection circuits.
Caution
Connections that exceed the rated input voltages can damage the computer and
the connected equipment. National Instruments is not liable for any damages resulting
from such connections.
Analog Output (PCI-4451/4453 Only)
The analog output section of the PCI-4451/4453 is software-configurable.
You can select different analog output configurations through application
software designed to control the PCI-4451/4453. The following sections
describe in detail each of the analog output categories. The PCI-4451/4453
has two channels of analog output voltage at the I/O connector.
Output Mode
♦
PCI-4451
The PCI-4451 has DIFF outputs. You can configure the outputs as an SE
channel using the BNC-2140 DSA accessory. For more information, 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.
