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Glossary
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National Instruments Corporation
G-5
dynamic configuration
A method of automatically assigning logical addresses to VXIbus devices
at system startup or other configuration times. Each slot can contain one or
more devices. Different devices within a slot can share address decoding
hardware.
dynamic range
The ratio of the largest signal level a circuit can handle to the smallest
signal level it can handle (usually taken to be the noise level), normally
expressed in dB.
dynamically configured
device
A device that has its logical address assigned by the Resource Manager. A
VXI device initially responds at Logical Address 255 when its MODID line
is asserted. The Resource Manager subsequently assigns it a new logical
address, which the device responds to until powered down.
E
embedded controller
An intelligent CPU (controller) interface plugged directly into the VXI
backplane, giving it direct access to the VXIbus. It must have all of its
required VXI interface capabilities built in.
EPROM
Erasable Programmable Read-Only Memory (ROM) that can be erased
(usually by ultraviolet light exposure) and reprogrammed.
event
Signals or interrupts generated by a device to notify another device of an
asynchronous event. The contents of events are device-dependent.
external controller
In this configuration, a plug-in interface board in a computer is connected
to the VXI mainframe via one or more VXIbus extended controllers. The
computer then exerts overall control over VXIbus system operations.
external trigger
A voltage pulse from an external source that triggers an event such as A/D
conversion.
F
floating signal sources
Signal sources with voltage signals that are not connected to an absolute
reference or system ground. Also called nonreferenced signal sources.
Some common example of floating signal sources are batteries,
transformers, or thermocouples.
ft
feet