PLC Final Exam Questions

A __ Circuit is a method of maintaining current flow after a momentary switch has been pressed and release.

• Seal-in
• Disconnect
• Bypass
• Short-circuit

An AND gate operates on the same principle as a

• Series circuit

• Closed circuit

• Parallel circuit

• Schematic circuit

Discrete means that each output or input has two states: ______ and _______

• True and False

• Analog and Digital

• Biased and Unbiased

• Latched and Unlatched

Tags

NGSS.MS-PS4-3

What is ScanTime?

• The time it takes for a signal to travel from the plc to the output device

• The time required for one full cycle, provides a measure of the speed of response of the PLC

• The time needed to install a new software update on the plc

• The duration it takes for a plc to reboot after a power failure

PLCs were originally designed as replacements for

• Resistance

• Relay control panels

• Transducer

• Microcomputers

During each scan cycle the processor reads all the inputs, takes these values, and energizes or De-energizes the outputs according to the user program.

• Program scan

• Input scan

• Maintenance scan

• Housekeeping scan

Programmable logic controllers are categorized according to the:

• Number of I/O points

• Size of Control program

• Power rating of the I/O modules

• Voltage rating of field devices

______ Relays are used where it is necessary for context to stay open and or closed even though the coil is energized momentarily.

• Latch
• Unlatch

• Coiled

• Discrete

Hardwired logic is programmable and easily changed.

• True

• False

• Only if quick disconnects are used in the wiring

• If the change is relatively simple

A XIC input can be best compared to a(n) ___________

• Normally closed switch

• Transformer

• Transmitter

• Normally open switch