Title: Chapter #9
Course: Programmable Logic Controls (IC 107-IC 107) > Section: Assessments

Q: Forcing functions are often used:
- to continue a machine process until a faulty field device can be repaired.
- for testing purposes during an initial start-up.
- for troubleshooting purposes.
A: to continue a machine process until a faulty field device can be repaired.

Q: If the MCR output is turned off or de-energized, all nonretentive rungs below the MCR will be de-energized.
- True
- False
A: True

Q: Jumping to a subroutine does not cause any rungs of the main program to be skipped over.
- True
- False
A: True

Q: PLC emergency stop circuits should be:
- hardwired outside the controller program.
- programmed as part of the master control reset instruction.
- programmed as part of the zone control last state instruction.
- programmed as an immediate input instruction.
A: hardwired outside the controller program.

Q: Random forcing of given inputs or outputs can cause equipment damage.
- True
- False
A: True

Q: Retentive instructions should not normally be placed within an MCR zone because they will remain in their last active state when the instruction goes false.
- True
- False
A: True

Q: The _________ is the target for the jump instruction.
- LBL
- TND
- IOT
- RET
A: LBL

Q: The JMP and LABEL instructions allow a processor to:
- return to the beginning of a program.
- take a shorted route to the end of the program.
- skips sections of the program, reducing scan time.
- create a fault condition.
A: return to the beginning of a program.

Q: The JMP instruction does not contribute to logic continuity and, for all practical purposes, is always logically true.
- True
- False
A: False

Q: The jump (JMP) instruction is used to jump over certain program instructions if certain conditions exist.
- True
- False
A: True

Q: The jump-to-subroutine instruction can save a great deal of duplicate programming in cases:
- that require the programming of several timers
- that require the programming of several counters.
- where a machine has a portion of its cycle that must be repeated several times during one machine cycle.
A: that require the programming of several timers

Q: The label (LBL) instruction is:
- always logically true.
- has the same address as the jump instruction with which it is used.
- is used to identify the ladder rung that is the target destination of the JMP instruction.
A: always logically true.

Q: The label address must match that of the jump instruction with which it is used.
- True
- False
A: True

Q: The main advantage to the jump-to-label instruction is that:
- any number of rungs may be programmed between the jump and label rungs.
- it allows you to use one set of condition instructions to control multiple outputs.
- it allows you to use one set of condition instructions to control multiple inputs.
- it has the ability to reduce the processor scan time.
A: any number of rungs may be programmed between the jump and label rungs.

Q: The master control instruction is used as a substitute for a hardwired emergency stop switch.
- True
- False
A: False

Q: The MCR instruction establishes a zone in the user program in which all nonretentive outputs can be:
- turned on simultaneously.
- turned off simultaneously.
- turned on in a defined sequence.
- turned off in a defined sequence.
A: turned on simultaneously.

Q: The use of immediate instructions:
- increases the total scan time of the program.
- decreases the total scan time of the program.
- increases the number of rungs that can be programmed.
- decreases the number of rungs that can be programmed.
A: increases the total scan time of the program.

Q: When programming an MCR instruction to control a fenced zone, an MCR rung with no conditional inputs is placed at the beginning of the zone and an MCR rung with conditional inputs is place at the end of the zone.
- True
- False
A: False

Q: When the jump-to-label instruction is executed, the outputs of the jumped rungs:
- are all energized.
- are all de-energized.
- are all immediately updated.
- remain in their last state.
A: are all energized.

Q: When the processor scan reaches the RET instruction, it will return the processor to the:
- start of the program.
- end of the program.
- rung above the JSR instruction.
- rung below the JSR instruction.
A: start of the program.