Chapter 84 Flashcards

0
Q
When a process variable has no method of sending information to the final control element, the system is know as:
A) an automatic system
B) an open loop system
C) a cascading system
D) a feedback system
E) a feed forward system
A

B) an open loop system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
1
Q
A variable adjusted in order to maintain or achieve a desired value of another variable is termed the:
A) process variable
B) final variable
C) manipulated variable
D) controlled variable
E) transmitted variable
A

C) manipulated variable

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q
The apparatus that converts current signals to pneumatic and pneumatic to current signals is a:
A) diverted
B) inducer
C) inverter
D) transducer
E) transformer
A

D) transducer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q
A device that converts the measurement of a sensing device into a signal is a:
A) controller
B) logic device
C) primary element
D) relay switch
E) transmitter
A

E) transmitter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

State the most common signal range for pneumatic instrument signals:

A

20 - 100 kPa

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

List two types of electrical signals used in control systems, and give examples of where each might be used.

A

Voltage signals - used with switching devices such as scanners, low water fuel cutoff, etc
Current signals - used for analog instruments where signals must be sent over long distances

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

One common example of a photoelectric transducer used on boilers is the_____ scanner.

A

Flame

How well did you know this?
1
Not at all
2
3
4
5
Perfectly