Title: EIC225 Ch 6 Test Pool
Course: Open EIC225 Programmable Controllers

Q: An electromechanical relay uses electromagnetism to operate contacts.
- True
- False
A: True

Q: A normally closed (NC) relay contact is closed when current flows through the coil.
- True
- False
A: False

Q: A relay usually will have only one coil but a number of different contacts.
- True
- False
A: True

Q: In general, control relay contacts are designed to handle higher currents than contactors.
- True
- False
A: False

Q: In general, PLC output modules are designed to switch high current loads directly.
- True
- False
A: False

Q: In a magnetic motor starter, the control circuit is required to handle the full load current of the motor.
- True
- False
A: False

Q: A selector switch is rotated to open and close contacts.
- True
- False
A: True

Q: Proximity switches usually sense the presence or absence of a target by means of physical contact.
- True
- False
A: False

Q: A small current flows through a solid-state proximity sensor even when the output is turned OFF.
- True
- False
A: True

Q: An inductive proximity sensor is actuated by conductive and nonconductive materials.
- True
- False
A: False

Q: LED light sources used in photoelectric sensors normally emit a continuous beam of light.
- True
- False
A: True

Q: A through-beam photoelectric sensor is used to detect the light beam reflected from a target.
- True
- False
A: False

Q: Changes to dual-in-line package (DIP) switch settings are made mainly during installation.
- True
- False
A: True

Q: Ultrasonic sensors operate using high-frequency light waves.
- True
- False
A: False

Q: Weight strain gauges operate by detecting small changes in temperature.
- True
- False
A: True

Q: Reed switches are activated by magnetism.
- True
- False
A: True

Q: Encoders are used in applications where positions have to be precisely determined.
- True
- False
A: True

Q: Fiber optic sensor systems are completely immune to all forms of electrical interference.
- True
- False
A: True

Q: All servo motors operate in open loop.
- True
- False
A: False

Q: Latching relays are used when it is necessary for contacts to stay open and/or closed, even though the coil is momentarily energized.
- True
- False
A: True

Q: The programmed latching relay instruction is retentive; that is, if the relay is latched, it will unlatch if power is lost and then restored.
- True
- False
A: False

Q: There is more than one correct way to implement the ladder logic for a given control process.
- True
- False
A: True

Q: Digital sensors are sometimes called discrete sensors because there are two discrete states: on or off.
- True
- False
A: True

Q: Strain gages are used for pressure/force sensing.
- True
- False
A: True

Q: A thru-beam sensor has the shortest sensing range of the three types of photo sensors.
- True
- False
A: False

Q: Hysteresis for sensors means that there is an on point and a separate off point.
- True
- False
A: True

Q: An electromagnet control relay is basically a(n):
- electromagnet used to switch contacts.
- electromagnet used to relay information.
- manually operated control device.
- pressure-operated control device.
A: electromagnet used to switch contacts.

Q: In the relay shown, the coil would be considered to be:
- energized.
- de-energized.
- operated from an ac source.
- both a and c.
A: energized.

Q: In the hardwired relay control circuit shown, when the switch is closed, CR coil is:
- energized, and the red and green lights are both on.
- de-energized, the red light is off, and the green light is on.
- energized, the red light is on, and the green light is off.
- energized, the red light is off, and the green light is on.
A: energized, the red light is on, and the green light is off.

Q: A contactor:
- is another name for a relay.
- is designed to handle heavy power loads.
- always has an overload relay physically and electrically attached.
- is a physically small relay.
A: is designed to handle heavy power loads.

Q: In the motor starter circuit shown, the main contacts M are:
- part of the power circuit.
- part of the control circuit.
- designed to handle the full load current of the motor.
- both a and c.
A: both a and c.

Q: The motor starter coil M is:
- part of the power circuit.
- energized to start the motor.
- energized only as long as the start button is pressed.
- All of the above.
A: energized to start the motor.

Q: Any overload current is sensed by the:
- starter coil.
- control contact M.
- OL coils.
- OL contact.
A: OL coils.

Q: The abbreviations NO (normally open) and NC (normally closed) represent the electrical state of switch contacts when:
- power is applied.
- power is not applied.
- the switch is actuated.
- the switch is not actuated.
A: the switch is not actuated.

Q: The pushbutton symbol shown, would be classified as a(n):
- NO pushbutton.
- NC pushbutton.
- break-before-make pushbutton.
- ON/OFF pushbutton.
A: break-before-make pushbutton.

Q: The device represented by the symbol is a:
- drum switch.
- selector switch.
- sequence switch.
- toggle switch.
A: selector switch.

Q: A limit switch is usually actuated by:
- hand.
- pressure.
- contact with an object.
- an electromagnet.
A: contact with an object.

Q: A proximity switch can be actuated:
- without any physical contact.
- by a change in light intensity.
- by a change in capacitance.
- by all of the these.
A: without any physical contact.

Q: The symbol shown is that for a:
- pressure switch.
- temperature switch.
- limit switch.
- level switch.
A: limit switch.

Q: The symbol shown is that for a:
- pressure switch.
- temperature switch.
- proximity switch.
- level switch.
A: level switch.

Q: The symbol shown is that for a:
- proximity switch.
- temperature switch.
- limit switch.
- level switch.
A: temperature switch.

Q: The symbol shown is that for a:
- pressure switch.
- temperature switch.
- limit switch.
- proximity switch.
A: pressure switch.

Q: The application shown is a typical application for a:
- level switch.
- temperature switch.
- proximity switch.
- limit switch.
A: proximity switch.

Q: The symbol shown is that for a:
- heater.
- horn.
- solenoid.
- motor.
A: solenoid.

Q: The symbol shown is that for a:
- solenoid valve.
- motor starter coil.
- overload relay coil.
- overload relay contact.
A: motor starter coil.

Q: The symbol shown is that for a:
- light sensor.
- heat sensor.
- pressure sensor.
- proximity sensor.
A: proximity sensor.

Q: The circuit shown is that of a:
- one-wire proximity sensor
- two-wire proximity sensor
- three-wire proximity sensor
- four-wire proximity sensor
A: two-wire proximity sensor

Q: Most proximity switches come equipped with an LED status indicator to:
- indicate that power is being applied to the switch.
- indicate that the target is within sensing range.
- indicate a blown fuse within the switch.
- verify the output switching action.
A: verify the output switching action.

Q: The resistor shown in the circuit:
- is called a bleeder resistor.
- is used to used to power the sensor continuously.
- allows enough current for the sensor to operate but not enough to turn on the input.
- all of these

*51. Capacitor proximity sensors:
A. are actuated by both conductive and nonconductive materials.
B. are actuated by conductive materials only.
C. produce an electromagnetic field.
D. have a long sensing range.
A: is called a bleeder resistor.

Q: An inductive proximity sensor is actuated by:
- a metal object.
- a light beam.
- a nonconductive material.
- any of these.
A: a metal object.

Q: The most common actuator for a reed switch is:
- a permanent or electromagnet.
- a light beam.
- application of pressure.
- a heat source.
A: a permanent or electromagnet.

Q: A(n) ____converts light energy directly into electric energy.
- LED
- phototransistor
- solar cell
- photoconductive cell
A: solar cell

Q: The light sensor shown would be classified as a:
- solar cell.
- photoconductive cell.
- photovoltaic cell.
- all of these.
A: photoconductive cell.

Q: The light source used in most industrial photoelectric sensors is a(n):
- LED.
- phototransistor.
- photovoltaic cell.
- miniature incandescent lamp.
A: LED.

Q: For the photoelectric sensor part 1 is the ___ and part 2 is the___.
- input, output
- primary, secondary
- transmitter, receiver
- high side, low side
A: transmitter, receiver

Q: Fiber optic sensors:
- are not affected by electrical interference.
- carry light signals.
- use a flexible cable containing tiny fibers.
*. all of these.
A: are not affected by electrical interference.

Q: Bar code scanners are used primarily for:
- data collection.
- temperature measurement.
- pressure measurement.
- flow measurement.
A: data collection.

Q: A(n) ___ operates by sending sound waves toward a target and measuring the time it takes for the pulses to bounce back.
- pressure sensor
- bar code scanner
- ultrasonic sensor
- flowmeter
A: ultrasonic sensor

Q: The force applied to a strain gauge causes it to bend and change its:
- temperature.
- resistance.
- voltage.
- current.
A: resistance.

Q: A thermocouple, when heated:
- produces a small dc voltage.
- produces a small ac voltage.
- increases its resistance value.
- decreases its resistance value.
A: produces a small dc voltage.

Q: The sensor illustrated is a:
- thermocouple.
- turbine flow meter.
- strain gauge load cell.
- retroreflective sensor.
A: turbine flow meter.

Q: A tachometer normally refers to a(n) ____ used for speed measurement.
- load cell
- capacitive proximity sensor
- ultrasonic sensor
- small generator
A: small generator

Q: An encoder is used to:
- encode signals from a scanner.
- decode signals from a scanner.
- change DC to AC.
- convert motion into a digital signal.
A: convert motion into a digital signal.

Q: An actuator is a device that:
- changes AC to DC.
- changes DC to AC.
- converts an electrical signal into mechanical movement.
- converts mechanical movement into an electrical signal.
A: converts an electrical signal into mechanical movement.

Q: Solenoid valves are available to control:
- oil flow.
- air flow.
- water flow.
- all of these
A: all of these

Q: A(n) ____ converts electrical pulses applied to it into discrete rotor movements.
- tachometer
- solenoid
- stepper motor
- electronic magnetic flowmeter
A: stepper motor

Q: All servo motors:
- operate in the closed-loop mode.
- operate in the open-loop mode.
- operate without feedback.
- both b and c.
A: operate in the closed-loop mode.

Q: The purpose of the M contact shown in the circuit is to:
- open the circuit in the case of a motor overload.
- start the motor from a remote location.
- keep the starter coil energized when the start button is released.
- keep the starter coil de-energized when the start button is released.
A: keep the starter coil energized when the start button is released.

Q: The electromagnetic latching relay:
- is used to lock in a condition.
- uses a latch coil to set and hold the relay in the latched position.
- uses an unlatch coil to disengage the mechanical latch.
- all of these.
A: all of these.

Q: For the programmed latching operation shown, which two instructions must have the same address?
- ON and OFF inputs.
- Latch and unlatch outputs.
- ON input and latch output.
- OFF input and unlatch output.
A: Latch and unlatch outputs.

Q: The Output Latch (OTL) instruction:
- can turn an output on, but it cannot turn the output off.
- is used only to turn a bit on and latch it on.
- allows the output to remain on even if the rung changes to false.
- all of these
A: all of these

Q: Programmed latching circuits are retentive. This means that if power is interrupted the output will ____ when power is returned.
- switch to the ON state
- switch to the OFF state
- remain in its original ON or OFF state
- flash ON and OFF
A: remain in its original ON or OFF state

Q: For the program shown, what is the address of the instruction associated with the pressure switch?
- I:1/0
- I:1/1
- I:1/2
- I:1/3
A: I:1/3

Q: What is the type of the instruction associated with the selector switch?
- OTE
- OTD
- XIC
- XIO
A: XIC

Q: Rung 1 will be True whenever the:
- pushbutton and limit switch are closed.
- selector switch and pressure switch are closed.
- selector switch and pushbutton are closed.
- pressure switch and pushbutton are closed.
A: pushbutton and limit switch are closed.

Q: Rung 2 will be True whenever:
- the pressure switch is closed.
- the pushbutton is closed.
- the selector switch is closed and rung 1 is True.
- either a or c.
A: either a or c.

Q: The instruction at address B3:1/3 is associated with:
- an internal relay coil.
- an external input device.
- an external output device.
- the solenoid.
A: an internal relay coil.

Q: If the XIC instruction at address I:1/3 is True:
- output B3:1/3 will also be True.
- output O:2/0 will also be True.
- input I:1/2 will also be True.
- both a and b.
A: output O:2/0 will also be True.

Q: Assume that a NC limit switch is substituted for the NO limit switch. For the circuit to operate in the same manner as before:
- the wires to the limit switch would have to be reversed.
- the address of the limit switch would have to be changed to I:1/4.
- the instruction representing the limit switch would have to be changed to an XIO.
- both b and c.
A: the instruction representing the limit switch would have to be changed to an XIO.

Q: With reference to the circuit and equivalent PLC program, when LS2 is actuated and LS1 is not:
- PLC input I:1/2 is True.
- PLC programmed rung 2 is False.
- pilot light PL2 is ON.
- both a and c.
A: PLC programmed rung 2 is False.

Q: When LS1 is actuated and LS2 is not:
- pilot light PL1 (O:2/5) is ON.
- pilot light PL2 (O:2/6) is ON.
- pilot light PL3 (O:2/7) is ON.
- all of these.
A: pilot light PL3 (O:2/7) is ON.

Q: When both LS1 and LS2 are not actuated:
- PLC program rung 1 is False.
- PLC program rung 2 is True.
- pilot light PL2 (O:2/6) is ON.
- all of these.
A: all of these.

Q: When both LS1 and LS2 are actuated:
- PLC program rung 2 is True.
- PLC program rung 3 is True.
- PLC program rung 4 is True.
- PLC program rung 5 is True.
A: PLC program rung 3 is True.