Unit 2 Operational Amplifiers Question 1 If a film of oil or

Unit 2 Operational Amplifiers

Question 1
If a film of oil or dirt forms on the head of a sensor, it will not affect the operation of the inductive type, but it may affect the capacitive type.
a.   True
b.   False

Question 2
Pressure, temperature, and level are often controlled by flow.
a.   True
b.   False

Question 3

The integral mode is effective in systems that require a fast response to the command signal.
a.   True
b.   False

Question 4
Which of the following conditions cause steady-state error?
a.   the load is too large
b.   a low gain setting of the proportional amplifier
c.   the command signal setting
d.   all of the above

Question 5
Current flows in a light detection device when _____ collide with its PN junction.
a.   electrons
b.   protons
c.   holes
d.   photons

Question 6
The size of the error signal effects the amplitude of a proportional mode output signal.
a.   True
b.   False

Question 7
A(n) _____ operational amplifier is used to perform the reset control mode.
a.   differentiator
b.   integrator
c.   difference
d.   comparator

Question 8
In batch production applications, ____ are the two most common process variables that must be regulated to control the rate of reaction.
a.   level and flow
b.   level and pressure
c.   temperature and pressure
d.   level and temperature

Question 9
A(n) _____ operational amplifier is used to perform the rate control mode.
a.   differentiator
b.   integrator
c.   difference
d.   comparator

Question 10
A ____ causes a controller to produce on and off signals at different values around the set point.
a.   dynamic response
b.   first order time lag
c.   deadband
d.   deadtime

Question 11
The proportional gain will be ____ if a 5 percent input change causes a 30 percent output change.
a.   1.5
b.   2
c.   3
d.   6

Question 12
If the error signal in a closed-loop system is changing very rapidly, the derivative output is _____.
a.   zero
b.   small
c.   large
d.   constant

Question 13
Steady-state error is also referred to as offset.
a.   True
b.   False

Question 14
Which control method is commonly associated with controlling the flowrate of materials to ensure the correct proportion of a mixture?
a.   feedback
b.   feedforward
c.   ratio
d.   proportional

Question 15
____ is the elapsed time between the instant a deviation of the controlled variable occurs, and the corrective action begins.
a.   Time lag
b.   Dynamic response
c.   Dead time
d.   Pure lag

Question 16
The longer the time duration that an offset error exists, the larger the _____ gain becomes.
a.   proportional
b.   integral
c.   derivative
d.   unit

Question 17
The _____ mode reduces overshoot and dampens oscillations of the controlled variable.
a.   proportional
b.   integral
c.   derivative
d.   on-off

Question 18
The lagging effect of the controlled variable behind the output state produced by the actuator is called _____.
a.   shadowing
b.   dragging
c.   hysterisis
d.   delaying

Question 19
What kind of controller action is related to the length of time an error persists?
a.   on/off
b.   proportional
c.   integral
d.   derivative

Question 20
An inductive proximity detector senses _____.
a.   metallic materials
b.   nonmetallic materials
c.   powdered materials
d.   granular materials

Question 21
The most common variable in a continuous process application that needs to be controlled is ____.
a.   pressure
b.   temperature
c.   flow
d.   level

Question 22
The ____ adjustment on the controller is used to change the derivative action.
a.   gain
b.   PB
c.   reset
d.   rate

Question 23
A system that continues to oscillate is described as being _____.
a.   stable
b.   unstable
c.   overdamped
d.   critically damped

Question 24
The derivative control function is not necessary if the controlled variable does not lag behind the changing controller output signal.
a.   True
b.   False

Question 25
The proportional gain will be 4 if the output changes by 80 percent when the input changes by ____ percent.
a.   10
b.   20
c.   80
d.   320

Question 26
Feedback systems work on the principle that the process must deviate from set point before control action is applied.
a.   True
b.   False

Question 27
To correct the steady-state error, an integral amplifier is added to the proportional system.
a.   True
b.   False

Question 28
The input to the controller is received from ____.
a.   a sensor
b.   a transmitter
c.   a transducer
d.   any of the above

Question 29
If the gain of a proportional controller is too high, it will cause the controlled variable to oscillate around the set point in the same manner as an on/off system.
a.   True
b.   False

Question 30
The controlled variable must deviate from the set point in an on/off controller to cause controlled action to occur.
a.   True
b.   False

Solution

1)    a.    True
2)    a.    True
3)    b.    False
4)    d.    all of the above
5)    d.    photons
6)    a.    True
7)    b.    integrator
8)    c.    temperature and pressure
9)    a.    differentiator
10) c.    deadband
11) d.    6
12) c.    large
13) a.    True
14) c.    ratio
15) c.    Dead time
16) b.    integral
17) c.    derivative
18) c.    hysterisis
19) c.    integral
20) a.    metallic materials
21) c.    flow
22) d.    rate
23) b.    unstable
24) a.    True
25) b.    20
26) a.    True
27) a.    True
28) d.    any of the above
29) a.    True
30) a.    True