PLC Midterm Review

Output field devices include all of the following except what?

• Lights

• Push-buttons

• Horns

• Valves

Discrete signals are signals that are ...

• off/on

• continuous

• 4-20mA

• not used in PLCs

Optical isolators in the PLC I/O modules are used to...

• read the internal operating temperature of the PLC

• step up the voltage

• power the CPU modules

• isolate field device and processor signal currents

Analog input modules convert an analog signal into a usable digital value for the processor using what?

• ASCII code

• Analog to digital converter circuit (A/D)

• Digital to analog converter circuit (D/A)

• Stepper modules

Volatile memory is ...

• easily altered and lost if power is removed

• sold on Wall Street

• unalterable and will retain if power is removed

• not used in PLCs

What is the type of memory where the PLC program lives in?

• ROM

• RAM

• GOAT

• nonvolatile

Identify which card type, slot number, and terminal point for the following address based address: O:5/12

• Input card, slot 5, terminal 12

• Input card, slot 12, terminal 5

• Output card, slot 5, terminal 12

• Output card, slot 12, terminal 5

The backplane in a modular style PLC is:

• communication to I/O cards

• on a printed circuit board that connects to I/O cards

• sometimes used to provide power to I/O cards

• all of the above

When creating a PLC Program, where are the input instructions located on the PLC ladder logic rung?

• left side of the PLC diagram ladder logic

• right side of the PLC diagram ladder logic

• at the end of the PLC diagram ladder logic program

Which type of PLC would be able to except additional input cards after it has been installed?

• fixed

• modular

• standalone

• portable