National Instruments 653X Manuale Utente

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Glossary
© National Instruments Corporation
G-3
channel
Pin or wire lead to which you apply or from which you read the analog or 
digital signal. For digital signals, you group channels to form ports. Ports 
usually consist of either four or eight digital channels.
CompactPCI
core specification defined by the PCI Industrial Computer Manufacturer’s 
Group (PICMG)
compiler
A software utility that converts a source program in a high-level 
programming language, such as LabVIEW, Basic, C or Pascal, into an 
object or compiled program in machine language. Compiled programs run 
10 to 1,000 times faster than interpreted programs. Some languages, such 
as Java, are compiled to an intermediate language that is interpreted at run 
time.
control signals
Signals that regulate/control the timing of your data transfer in handshaking 
I/O and pattern I/O. There are four control signals in your 653device: 
ACK (STARTTRIG), REQ, STOPTRIG, and PCLK.
counter/timer
 a circuit that counts external pulses or clock pulses (timing)
CPULL
A user-configurable 2.2 k
Ω internal resistor for control lines. You can 
connect the line to +5 VDC (pull up) or connect the line to ground (pull 
down
).
current sinking
the ability to dissipate current for analog or digital signals
current sourcing
the ability to supply current for analog or digital signals
D
DAQ
Data Acquisition—Collecting and measuring electrical signals from 
sensors, transducers, and test probes or fixtures and inputting them to a 
computer for processing. Also refers to collecting and measuring the same 
kinds of electrical signals with analog-to-digital and/or digital devices 
plugged into a PC, and possibly generating control signals with 
digital-to-analog and/or digital devices in the same PC.
Data In Valid
data generated by peripheral device that is ready for input to the 653X 
device
DC
direct current