Motor Control 3: Lesson 2 - Understanding Analog Signal Flashcards
What type of signal is continuous, varying from a minimum to a maximum value?
a. Analog
b. Discrete
a. Analog
What type of signal has only two states: ON and OFF?
a. Analog
b. Discrete
b. Discrete
A limit switch is an example of a(n) ______ signal.
a. analog
b. discrete
b. discrete
A(n) ______ converts from one analog signal range to a different analog signal range when the analog signal values do not match.
a. analog switch
b. signal conditioner
b. signal conditioner
0-10 VDC, 4-20 ma, and 3-15 psi are examples of what type of signal?
a. Analog
b. Discrete
a. Analog
Generally, _______ signals with a very low source resistance are less sensitive to electrical noise from welders and electric motor starters.
a. current
b. voltage
a. current
______ signals provide a continuous indication of the value or position of the variable or entity being monitored.
a. Analog
b. Discrete
a. Analog
What type of device has one type of analog signal as an input, and produces another type of analog signal as an output?
a. Analog switch
b. Signal conditioner
c. Signal converter
c. Signal converter
Which type of analog signal can be used to not only control the speed of a motor, but also the direction of rotation of the motor?
a. 0-10 VDC
b. 0-20 mA
c. ±5 VDC
c. ±5 VDC
A(n) ______ signal can be used to control the speed of a motor, determine the position of a valve, or indicate the level of a tank at every level as the tank fills or empties.
a. analog
b. discrete
a. analog
Analog devices connected using a current loop analog signal are connected in ______ with each other.
a. parallel
b. series
b. series
Analog devices connected using a voltage type analog signal are connected in ______ with each other.
a. parallel
b. series
a. parallel
A 1-5 VDC analog device can be used in a 4-20 mA DC loop circuit if a 250 ohm resistor is connected across the input to the device and the 4-20 mA DC current is routed through the resistor. The current signal produces the proper voltage to operate the 1-5 VDC device.
True or False
True
When analog control devices are located large distances from each other, which type of signal is preferable for installing the control wiring?
a. Current
b. Voltage
a. Current
A certain process control system utilizes a tank that is 10 feet tall. The transducer that measures the level of liquid in the tank is located 2 feet from the bottom of the tank. If a 1-5 VDC signal is used to monitor the top 8 feet of water in the tank, how much water is in the tank when the analog value read at the transducer is 3.5 VDC?
a. 5
b. 7
c. 9
Note: A 4 volt signal (5 V - 1 V) represents 8 feet of water in the tank. 4 V/8 feet = 0.5 volts per foot. 3.5 volts represents 3.5 V - 1 V = 2.5 volts of signal. 2.5 V/0.5 V = 5 feet of water. Since the transducer is only monitoring the top 8 feet of water in the tank, the height of water in the tank is 2 feet (not monitored) + 5 feet (the measured value) = 7 feet. There are 7 feet of water in the tank.
