PLC'S Chapters 1&2 Flashcards
The number and type of I/Os cannot be changed in a fixed PLC.
True
In a PLC system, there is a physical connection between field inputs devices and output devices.
False
The input/output system forms the interfaces through which field devices are connected to the controller.
True
A PLC is basically a computer designed for use in electrical control applications.
True
Removing the programming device from the PLC will not affect the operation of the user program.
True
When dealing with PLC memory, one K of memory represents 1024.
True
The number of I/O points does not affect the memory size required for a PLC installation.
True
Modifying relay-type process control circuits usually involves changing the: A. Circuit wiring B. Input circuit modules C. Output circuit modules D. Circuit operating voltage levels
A
The control plan stored in the PLC is called: A. A Program B. A Boolean ladder C. FORTRAN D. A microprocessor
A
When a field device contact connected to the input module closes:
A. A logic 1 is recorded in the memory location of the coil with the same address.
B. A logic 1 is recorded in the memory location of the contact with the same address
C.A logic 0 is recorded in the memory location of the contact with the same address
D.A logic 1 is recorded in the memory location of the contact with the same address.
D
The scan time is the time required:
A. To record the status of all input devices.
B. To record the status of all output devices.
C. To execute one cycle of the total program.
D. For the information to pass from input to output
C
Block No.4 of the PLC block diagram represents the:
A. Memory
B. Programming device
C. Input module
D. CPU
C
Which module of the PLC connects directly to fiel devices such as pilot lights, motor starters, and solenoids. A. Input B. Output C. Power supply D. Memory
B
PLC software that runs on a personal computer can be used to: A. Write a PLC program B. Document a PLC program C. Monitor the control process D. All the above
D
I/O modules are designed to plug into a slot or connector.
True
The processor may perform functions such as timing, counting, and comparing in addition to logic processing.
True
Memory is where the control plan is held or stored in the controller.
True
When a new program is loaded into a PLC’s memory, the old program that was stored in the same location is over-written and essentially erased.
True
Most PLC programming software will allow you to develop programs on another manufacturer’s PLC.
False
Analog signals can have only two states.
False
Discrete means that each input or output has two states: turn (on) or false (off).
True
Digital modules are also called discrete modules.
True
An analog input or output is a signal that varies continuously within a certain range.
True
Optical isolation used in I/O modules helps to reduce the effects of electrical noise.
True
A \_\_\_ is an example of a device that be controlled by a discrete output from a PLC. A. Pushbutton B. Motor starter C. Limit switch D. All of these
B
One function of a PLC input interface module is to: A. Accept signals from field devices and convert them into signals that can be used by the processor. B. Convert signals from the processing unit into values that can be used to control the machine or process. C. Input signals from the programming device and convert them into signals that can be used by the CPU. D. Interpret and execute the user program that controls the machine or process
A
A discrete output interface module is designed to provide:
A. Output voltages only in the 5 VDC range. B. Varying AC or DC voltages depending on the type of module selected. C.ON/OFF switching of the output field device. D. Binary-coded outputs.
C
The following statement that does not apply to the optical isolator circuit used in I/O modules is that it:
A. Separates high voltage and low voltage circuits.
B. Rectifies AC signals
C. Prevents damage caused by line voltage transients.
D. Reduces the effect of electrical noise.
B
Which of the following is not a function of a PLC programming device? A. To enter the user program B. To change the user program C. To execute the user program D. To monitor the user program
C
The I/O system provides an interface between: A. Input modules and output modules. B. The CPU and field equipment. C. The CPU and I/O rack. D. The I/O rack and I/O modules.
B
The Allen-Bradly SLC-500 address I:2/4 refers to an: A. Input module in slot 4, terminal 2. B. Output module in slot 4, terminal 2 C. Input module in slot 2, terminal 4 D. Output module in slot 2, terminal 4
C
The Allen-Bradly SLC-500 address O:3/0 refers to an: A. Input module in slot 3, terminal 0. B. Output module in slot 3, terminal 0 C. Input module in slot 0, terminal 3 D. Output module in slot 0, terminal
B
