Title: Module 1 Test
Course: Open EIC225 Programmable Controllers

Q: A human machine interface (HMI)
- allows the user to monitor a process.
- allows the user to control a process.
- can provide a graphical representation of a process.
- All of the above.
A: All of the above.

Q: A personal computer communicates with the PLC processor via a serial or parallel data communications link.
- True
- False
A: True

Q: A PLC is basically a computer designed for use in electrical control applications.
- True
- False
A: True

Q: A PLC power supply module does not normally supply power to the field devices.
- True
- False
A: True

Q: At the start of the PLC scan the:
- status of all inputs are read.
- status of all outputs are updated.
- program is executed.
- diagnostics and communications tasks are executed.
A: status of all inputs are read.

Q: Basically, the function of a PLC is to:
- amplify various weak signal sources.
- control a high voltage output with a low voltage input.
- control the speed of motors.
- make logical decisions and control outputs based on them.
A: make logical decisions and control outputs based on them.

Q: Block No.1 of the PLC block diagram represents the:
- CPU unit.
- programming device.
- input module.
- output module.
A: programming device.

Q: Block No. 2 of the PLC block diagram represents the:
- memory.
- programming device.
- input module.
- power supply module.
A: memory.

Q: Block No. 3 of the PLC block diagram represents the:
- CPU unit.
- programming device.
- input module.
- output module.
A: CPU unit.

Q: Block No. 4 of the PLC block diagram represents the:
- memory.
- programming device.
- input module.
- CPU.
A: input module.

Q: Block No. 5 of the PLC block diagram represents the:
- memory.
- power supply module.
- input module.
- output module.
A: output module.

Q: Block No. 6 of the PLC block diagram represents the:
- processor module.
- power supply module.
- input module.
- output module.
A: power supply module.

Q: Field or real-world devices refer to:
- input devices only.
- output devices only.
- load devices only.
- all devices that are physically wired to the PLC.
A: all devices that are physically wired to the PLC.

Q: For there to be a continuous logic path from left to right across the rung:
- I/1, 1/2, and 1/3 must all be at logic 1.
- I/1, 1/2, and 1/3 must all be at logic 0.
- I/1 and 1/2 or 1/3 must be at logic 1.
- I/1 and 1/2 or 1/3 will be at logic 0.
A: I/1 and 1/2 or 1/3 must be at logic 1.

Q: In a PLC system, there is a physical connection between field input devices and output devices.
- True
- False
A: True

Q: In order to energize the starter coil:
- the pressure switch, and the temperature switch, and the manual pushbutton must be closed.
- the pressure switch, or the temperature switch, or the manual pushbutton must be closed.
- the pressure switch, and the temperature switch, or the manual pushbutton must be closed.
- All of the above.
A: the pressure switch, and the temperature switch, or the manual pushbutton must be closed.

Q: _________ I/Os are typical of small PLCs that come in one package with no separate removable units.
- Fixed
- Modular
- Digital
- Analog
A: Fixed

Q: Modifying relay-type process control circuits usually involves changing the:
- circuit wiring.
- input circuit modules.
- output circuit modules.
- circuit operating voltage levels.
A: circuit wiring.

Q: One disadvantage of modular I/O is its lack of flexibility.
- True
- False
A: False

Q: PLC proprietary architecture:
- is the opposite to open architecture.
- makes it more difficult to connect to devices made by other PLC manufacturers.
- does not allow programs to be interchanged between different PLC manufacturers.
- All of the above.
A: All of the above.

Q: PLC software that runs on a personal computer can be used to:
- write a PLC program.
- document a PLC program.
- monitor the control process.
- All of the above.
A: All of the above.

Q: PLCs were originally designed as replacements for:
- microcomputers.
- relay control panels.
- analog controllers.
- digital controllers.
A: relay control panels.

Q: PLC systems usually require as much space in an enclosure as equivalent hardwired relay systems.
- True
- False
A: False

Q: Plug-in compartments allow I/O modules to be easily connected and replaced.
- True
- False
A: True

Q: Removing the programming device from the PLC will not affect the operation of the user program.
- True
- False
A: True

Q: Software installed and run on a personal computer can be used to write a PLC program.
- True
- False
A: True

Q: The central processing unit:
- looks at the inputs, makes the decisions based on the program, and sets the outputs.
- looks at the outputs, makes the decisions based on the program, and sets the inputs.
- serves only to store the program in memory.
- serves only to supply power to the backplane.
A: looks at the inputs, makes the decisions based on the program, and sets the outputs.

Q: The control plan stored in the PLC is called:
- a program.
- a Boolean ladder.
- FORTRAN.
- a microprocessor.
A: a program.

Q: The devices connected to the terminals would be classified as:
- field input devices.
- internal input instructions.
- field output devices.
- internal output instructions
A: field input devices.

Q: The diagram shown is a:
- relay schematic.
- ladder logic program.
- input module wiring.
- output module wiring.
A: input module wiring.

Q: The diagram shown is that of a
- hardwired relay schematic.
- ladder logic program.
- input module schematic.
- output module schematic.
A: hardwired relay schematic.

Q: The input/output system forms the interfaces through which field devices are connected to the controller.
- True
- False
A: True

Q: The main difference between a PLC and relay control system is that:
- different types of input devices are used.
- different types of output devices are used.
- different input and output voltage levels are used.
- one uses hardwired relay control logic and the other uses programmed instructions.
A: one uses hardwired relay control logic and the other uses programmed instructions.

Q: The number and type of I/Os cannot be changed in a fixed PLC.
- True
- False
A: True

Q: The number of I/O points does not affect the memory size required for a PLC installation.
- True
- False
A: False

Q: The output interface module connects to:
- sensing devices such as switches or pushbuttons.
- load devices such as lamps or solenoids.
- a programming device such as a computer.
- All of the above.
A: load devices such as lamps or solenoids.

Q: The PLC power supply module normally is rated to provide the power for:
- all field devices.
- input field devices only.
- output field devices only.
- PLC backplane and I/O modules.
A: PLC backplane and I/O modules.

Q: The power required to operate the logic circuits of the processor unit is typically:
- low voltage ac.
- high voltage ac.
- low voltage dc.
- high voltage dc.
A: low voltage dc.

Q: The programmable controller operates in real time.
- True
- False
A: True

Q: The programming device must be connected to the controller to run the program.
- True
- False
A: False

Q: The programming device:
- is used to enter the program into the memory of the processor.
- is commonly a personal computer.
- can be a hand-held device.
- All of the above.
A: All of the above.

Q: The programming device must be connected to the controller:
- at all times.
- when entering a program.
- when monitoring a program.
- both b and c.
A: both b and c.

Q: The scan time is the time required:
- to record the status of all input devices.
- to record the status of all output devices.
- to execute one cycle of the total program.
- for the information to pass from input to output.
A: to execute one cycle of the total program.

Q: The symbol -| |- in a ladder logic diagram:
- can be thought of as a normally open contact.
- represents a capacitor.
- is always at logic 0.
- is always at logic 1.
A: can be thought of as a normally open contact.

Q: The symbol -()- in a ladder logic diagram represents a:
- set of normally closed contacts.
- virtual relay coil.
- seal-in contact.
- field input sensing device.
A: virtual relay coil.

Q: The voltage that would be present between the DC common and terminal 4 with the pushbutton open would be approximately:
- 0 volts.
- 6 volts.
- 12 volts.
- 24 volts.
A: 0 volts.

Q: The voltage that would be present between the DC common and terminal 4 with the pushbutton closed would be approximately:
- 0 volts.
- 6 volts.
- 12 volts.
- 24 volts.
A: 24 volts.

Q: Unlike personal computers, PLCs are:
- equipped with input and output modules.
- equipped with a control programming language.
- designed for the industrial environment.
- All of the above.
A: All of the above.

Q: When a field device contact connected to the input module closes:
- a logic 1 is recorded in the memory location of the coil with the same address.
- a logic 1 is recorded in the memory location of the contact with the same address.
- a logic 0 is recorded in the memory location of the coil with the same address.
- None of these are correct.
A: a logic 1 is recorded in the memory location of the contact with the same address.

Q: When dealing with PLC memory, one K of memory represents 1024.
- True
- False
A: True

Q: Which of the following is not an advantage that PLCs offer over the conventional relay-type of control system?
- Smaller size
- Less expensive
- Higher current capacity
- More reliable
A: Higher current capacity

Q: Which of the following is not a factor effecting the memory size needed for a particular PLC installation?
- Voltage rating of field devices
- Number of I/O points
- Size of control program
- Supervisory
A: Voltage rating of field devices