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
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
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
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
4
Q
State the most common signal range for pneumatic instrument signals:
A
20 - 100 kPa
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
6
Q
One common example of a photoelectric transducer used on boilers is the_____ scanner.
A
Flame