National Instruments 371685C-01 用户手册
Glossary
© National Instruments Corporation
G-5
R
ramp
The total (transient plus steady-state) time response resulting from a sudden
increase in the rate of change from zero to some finite value of input
stimulus.
increase in the rate of change from zero to some finite value of input
stimulus.
reentrant execution
Mode in which calls to multiple instances of a function can execute in
parallel with distinct and separate data storage.
parallel with distinct and separate data storage.
S
s
Seconds.
setpoint (SP)
An input variable that sets the desired value of the controlled process
variable.
variable.
span
The algebraic difference between the upper and lower range values.
T
time constant (T)
In process instrumentation, the value T (in minutes) in an exponential
response term, A exp (–t/T), or in one of the transform factors, such as
1+sT.
response term, A exp (–t/T), or in one of the transform factors, such as
1+sT.
trapezoidal integration
A numerical integration in which the current value and the previous value
are used to calculate the addition of the current value to the integral value.
are used to calculate the addition of the current value to the integral value.
V
V
Volts.
W
windup area
The time during which the controller output is saturated at the maximum or
minimum value. The integral action of a simple PID controller continues to
increase (wind up) while the controller is in the windup area.
minimum value. The integral action of a simple PID controller continues to
increase (wind up) while the controller is in the windup area.