WorksheetsLesson 9 PLC Counter
Total questions: 11
Worksheet time: 6mins
Which scenario best describes how a preset counter operates in an automation system?
It changes limits based on ambient temperature fluctuations
It resets automatically at random intervals during operation
It displays totals but never affects external circuits
It triggers an output when the count reaches set limits
A mechanical counter with an actuating lever is being used to tally parts. What single action increases the tally by one?
Turning the housing to engage internal gears
Pressing the side pushbutton to reset to zero
Moving the lever once then holding it forward
Moving the lever once and letting it return
An electronic counter on a conveyor must add one count for each part and subtract one when a part is removed before packaging. Which configuration satisfies this requirement?
Manual reset with no external sensors
Up counting only using a photocell sensor
Down counting only using a limit switch
Combined up/down counting with two sensors
In a coil-formatted CTU counter, what event causes the accumulated value to increment by one?
Any change of input state either direction
A true-to-false transition of the input
A false-to-true transition of the input
A rising edge only when output is closed
When the accumulated count reaches the preset in a CTU, what happens to the counter output contact?
It energizes and closes for use as NO or NC
It pulses once then returns open
It latches permanently until power cycle
It opens and disables all rungs
In a PLC, what happens to a counter’s accumulated value after a processor shutdown and subsequent power-up, assuming no reset condition is active?
It is restored to the prior value
It clears to zero automatically
It doubles due to restart pulses
It randomly initializes to a preset
In the ladder program, which condition turns ON the Red pilot light (O:2/0)?
PB1 energized with counter not done
Counter Done Bit C5:1/DN is true
Accumulated value equals preset minus one
PB2 reset instruction is active
In a PLC-5/SLC 500 counter, which status bit indicates the counter has reached or exceeded the preset?
CU count-up enabled
DN done condition met
UN underflow detected
OV overflow detected
In RSLogix, which command is used to increment a counter on rising input transitions from a proximity switch?
CTU count-up on rising edges
RES reset on power cycle only
CTD count-down on falling edges
HSC high-speed with external module
In a one-shot (transitional) contact program, what best describes the behavior of the one-shot output once it is triggered?
Extends on-time proportionally with input duration
Turns on for one program scan then turns off
Remains off unless the input is latched
Alternates on and off for multiple scan cycles
An engineer needs to automatically clear a counter exactly once when an input goes from off to on. Which programming element should be used?
Standard maintained contact logic rung
On-delay timer with long preset value
Retentive counter with manual reset
One-shot transitional contact rung
