Question 1

For the programmed timer circuit shown,the pilot light should come on: 
A)as soon as the switch is closed.
B)before the switch is closed.
C)for 15 seconds after the switch is opened.
D)both a and c.

Accepted Answer

The circuit is designed so that as soon as the switch is closed, power flows to the timer and the pilot light. The timer then counts down for 15 seconds before opening the switch to turn off the pilot light. Therefore, the pilot light should come on as soon as the switch is closed (choice A) and should stay on for 15 seconds after the switch is opened (choice C). Therefore, the best choice is D (both A and C are correct).

Question 2

RES instructions are used with:
A)TOF timers
B)TON timers
C)RTO timers
D)all of these

Accepted Answer

The answer of RES instructions are used with:
A)TOF timers
B)TON timers
C)RTO...

Question 3

When the timing of a device is not reset on a loss of power,the timing is said to be:
A)continuous
B)holding
C)retentive
D)saved

Accepted Answer

If the timing is not reset on a loss of power, it means that the device is able to retain the timing information even when power is lost. This is known as a retentive timing device. A continuous timing device simply continues counting regardless of power status, while a holding device requires external inputs to hold or reset the timing. Saved is not a common term used to describe the timing function of a device.

Question 4

Which instruction can best be used to turn an output coil on or off after the rung has been false for a desired time?
A)RTO
B)TON
C)ON OFF
D)TOF

Accepted Answer

The TOF (Timer Off-Delay) instruction is used to turn an output coil on or off after the rung has been false for a desired time. It starts timing when the input condition becomes false.

Question 5

For the program shown,the timer accumulated time is set to zero anytime: 
A)PB1 is closed.
B)PB2 is closed.
C)PB1 is open.
D)PB2 is open.

Accepted Answer

The answer of For the program shown,the timer accumulated time...

Question 6

To reset a retentive timer,the:
A)AC time must be greater than the PR time.
B)PR time must be greater than the AC time.
C)AC time must equal the PR time.
D)none of these.

Accepted Answer

A retentive timer retains its accumulated (AC) value even when the controlling input is off. Resetting a retentive timer is not dependent on the relationship between the accumulated time and preset time (AC and PR times), but rather on a specific reset command or function within the control program. Therefore, none of the conditions listed (A, B, C) are correct for resetting a retentive timer.

Question 7

When addressing an RES instruction,it must be addressed to:
A)a TOF instruction.
B)a TON instruction.
C)any address other than that of the RTO instruction.
D)the same address as that of the RTO instruction.

Accepted Answer

When addressing an RES (Reset) instruction, it must be addressed to the same address as that of the RTO (Retentive Timer On) instruction. This is because the RES instruction resets the retentive timer set by the RTO instruction at that specific address. Therefore, choosing any other address or addressing a TOF (Timer On Flag) or TON (Timer On) instruction would not accomplish the desired result of resetting the retentive timer at the specific address.

Question 8

For the programmed timer circuit shown,assume the switch is closed for 5 seconds and than opened.After 12 seconds have elapsed motor(s)____ will still be operating. 
A)M1,M2,M3
B)M2,M3
C)M3
D)none of these

Accepted Answer

The answer of For the programmed timer circuit shown,assume the...

Question 9

The type of timer program shown is a: 
A)retentive on-delay.
B)retentive off-delay.
C)nonretentive off-delay
D)nonretentive on-delay.

Accepted Answer

The timer program shown is a retentive on-delay, as it retains the accumulated time whenever the input goes off and restarts timing when the input comes on again. The program uses an EN (enable) instruction to activate the timer and a TT (timer timed) instruction to accumulate time.

Question 10

The main difference between a PLC retentive and nonretentive timer is that the:
A)retentive timer can be programmed for much longer time delay periods.
B)nonretentive time can be programmed for much longer time delay periods.
C)retentive timer maintains the current time should power be removed from the device or when the timer rung goes false.
D)nonretentive timer maintains the current time should power be removed from the device or when the timer rung goes false.

Accepted Answer

The main difference between a retentive and nonretentive timer is that a retentive timer maintains the current time even when power is removed from the device or when the timer rung goes false. Nonretentive timers do not maintain the current time in these situations. The programming capabilities for time delay periods are not necessarily different between the two types of timers.

Question 11

For the programmed timers shown,the output of timer T4:5: 
A)turns on after a 10-s time delay and remains on.
B)turns off after a 2-s time delay and remains off.
C)turns on after a 3-s time delay and remains on.
D)is pulsed on and off at 1-s intervals.

Accepted Answer

The answer of For the programmed timers shown,the output of...

Question 12

The amount of time for which a timer is programmed is called the:
A)Preset
B)Desired Time
C)Set Point
D)Lapsed Time

Accepted Answer

The term "preset" refers to the amount of time for which a timer is programmed. It is the value that is entered into the timer before it is started. Once the timer is started, it counts down from the preset value until it reaches zero. Therefore, option A is the correct answer.

Question 13

The main difference between a TON and TOF timer is that the:
A)TON timer can maintain its accumulated time on loss of power or logic continuity.
B)TOF timer can maintain its accumulated time on loss of power or logic continuity.
C)TOF timer begins timing when logic continuity to the timing rung is lost.
D)TON timer begins timing when logic continuity to the timing rung is lost.

Accepted Answer

The main difference is that a TOF (Timer Off-Delay) timer begins timing when logic continuity to the timing rung is lost, whereas a TON (Timer On-Delay) timer starts timing when it receives logic continuity.

Question 14

For the program shown,the timer starts timing when: 
A)PB1 is closed.
B)PB2 is closed.
C)both PB1 and PB2 are closed.
D)either PB1 or PB2 is closed.

Accepted Answer

The answer of For the program shown,the timer starts timing...

Question 15

The operation of a PLC retentive timer is similar to that of an:
A)electromagnetic pneumatic timer.
B)electromechanical motor-driven timer.
C)off-delay timer.
D)on-delay timer.

Accepted Answer

Electromechanical motor-driven timers, like PLC retentive timers, maintain their state (time value) even when the controlling signal is removed, allowing them to "retain" the timing operation progress similar to how a PLC retentive timer would.

Question 16

The interconnecting of timers is commonly called:
A)grouping.
B)programming.
C)sequencing.
D)cascading.

Accepted Answer

The interconnecting of timers is commonly called cascading. This is because multiple timers are connected in a chain or cascade, with each timer triggering the next one in the sequence.

Question 17

Unlike the TON timer,the RTO timer requires a(n):
A)timer reset instruction.
B)input condition instruction.
C)internal relay instruction.
D)instantaneous contact instruction.

Accepted Answer

The RTO timer requires a timer reset instruction to restart the timing process, while the TON timer does not have a reset instruction, as it automatically resets when the accumulated time reaches the preset value. The other options (B, C, D) do not apply to the operation of the RTO timer.

Question 18

For the programmed timer circuit shown,when the switch is initially closed motor(s)_____ start(s)immediately. 
A)M1
B)M2
C)M3
D)all of these

Accepted Answer

When the switch is initially closed, power is immediately applied to the 555 timer IC, which triggers the output to go high. This high signal is then applied to all three relays, which activate their respective motor(s). Therefore, all of the motors (M1, M2, and M3) start immediately.

Quiz 7: Programming Timers

For the programmed timer circuit shown,the pilot light should come on:

RES instructions are used with:

When the timing of a device is not reset on a loss of power,the timing is said to be:

Which instruction can best be used to turn an output coil on or off after the rung has been false for a desired time?

For the program shown,the timer accumulated time is set to zero anytime:

To reset a retentive timer,the:

When addressing an RES instruction,it must be addressed to:

For the programmed timer circuit shown,assume the switch is closed for 5 seconds and than opened.After 12 seconds have elapsed motor(s) ____ will still be operating.

The type of timer program shown is a:

The main difference between a PLC retentive and nonretentive timer is that the:

For the programmed timers shown,the output of timer T4:5:

The amount of time for which a timer is programmed is called the:

The main difference between a TON and TOF timer is that the:

For the program shown,the timer starts timing when:

The operation of a PLC retentive timer is similar to that of an:

The interconnecting of timers is commonly called:

Unlike the TON timer,the RTO timer requires a(n) :

For the programmed timer circuit shown,when the switch is initially closed motor(s) _____ start(s) immediately.