Exercises

104 PLC programming exercises, beginner to expert. Solve in your browser, graded by automated tests. 20/104 built.

#	Title	Difficulty	Status	Summary
1	Lamp Follow	easy		Turn on a lamp while a push button is pressed and off when released.
2	Lamp Inverted	easy		Turn off a lamp while a push button is pressed and on when released.
3	Two-Button Lamp	easy		Turn on a lamp only when both push buttons are pressed at once.
4	Either-Button Lamp	easy		Turn on a lamp when either push button is pressed and off when both are released.
5	Select Between	easy		A BOOL select input chooses between two inputs to route to the output.
6	Start/Stop Motor	easy		Latch a motor running on Start press and drop it on Stop press.
7	Press-Toggle Lamp	easy		Flip the lamp state on each rising edge of the push button.
8	Rising Edge	easy		Produce a single-scan pulse on every 0-to-1 transition of a BOOL input.
9	Count Up	easy		Up-counter with a count input, reset, and a Done output that fires when count reaches 10.
10	Count Up Down	easy		Bidirectional counter with separate Up and Down inputs that tracks a running balance.
11	Batch Counter	easy		Pulse BatchReady every 5 trigger events and track the running batch count.
12	On Delay	easy		Drive the output high once the input has stayed high continuously for 1 second.
13	Off Delay	easy		Keep the output high for 2 seconds after the input goes low.
14	Flasher	easy		Flash the output at 1 Hz (1 second on, 1 second off) while enable is high.
15	Scale	easy		Scale a sensor reading from 4-20 mA into a 0-100 °C output.
16	Clamp	easy		Constrain a numeric input between 0 and 100.
17	Sign Check	easy		Output Negative, Zero, and Positive flags by comparing a numeric input to zero.
18	Debounce	medium		Filter contact bounce by ignoring input transitions shorter than a preset time.
19	Hysteresis	medium		Set the output true at the high setpoint and false at the low setpoint to avoid chatter.
20	Traffic Light Simple	medium		Drive a one-way traffic light through red, green, and amber phases on a timer.
21	Clamp with Overflow	medium	coming	Constrain a numeric input between Min and Max bounds and raise flags when limits are hit.
22	Count Up Down with Bounds	medium	coming	Bidirectional counter with upper and lower bounds, and flag outputs when the limits are hit.
23	Scale (Configurable)	medium	coming	Linearly scale a raw input to engineering units between two tunable endpoints.
24	Compare Pair	medium	coming	Output Less, Equal, and Greater flags by comparing two numeric inputs.
25	Xor Gate	easy	coming	Turn on a lamp when exactly one of two push buttons is pressed and off otherwise.
26	Voting Lamp	easy	coming	Light a lamp when at least two of three push buttons are pressed.
27	Falling Edge	easy	coming	Produce a single-scan pulse on every 1-to-0 transition of a BOOL input.
28	Pulse	easy	coming	Produce a 1-second output pulse on each rising edge of the trigger input.
29	Long Press	medium	coming	Fire a single-scan pulse when the input is released after being held continuously for at least 2 seconds — short taps produce no output.
30	Watchdog Alarm	medium	coming	Raise an alarm if the heartbeat input fails to pulse within the timeout.
31	Run Hours	medium	coming	Accumulate the run time of a BOOL input in seconds with a manual reset.
32	Delayed Shutdown	medium	coming	Hold the run-OK output high for a cooldown period after Stop is pressed.
33	Rate of Change	medium	coming	Output the rate of change of an analog input in engineering units per second.
34	Streaming Average	medium	coming	Compute a rolling average over the last N samples streamed one per scan.
35	Min Max Tracker	medium	coming	Track the minimum and maximum of an analog input until a Reset input is pulsed.
36	Energy Meter	medium	coming	Integrate a power input over time to produce accumulated energy with a manual reset.
37	Level Alarm	medium	coming	Produce Hi and Lo alarm outputs around setpoints with a deadband to avoid chatter.
38	Tank Fill	medium	coming	Open a fill valve until the tank level reaches the setpoint and close within deadband.
39	Temp Controller	medium	coming	Run an on-off temperature controller using hysteresis around a setpoint.
40	Ramp	medium	coming	Ramp the output from its current value to the target at a given rate per second.
41	VFD Speed Ref	medium	coming	Convert an operator percent (0 to 100) into a raw VFD speed reference.
42	Lead Lag	medium	coming	First-order lead-lag filter for process modeling, smoothing, and feedforward control.
43	Pump Duty	medium	coming	Alternate two pumps in lead and lag roles based on accumulated run hours.
44	Dosing	medium	coming	Pulse a dispenser until a target weight is reached with overshoot compensation.
45	Flow Totalizer	medium	coming	Integrate a flow rate input to produce a totalized volume with a manual reset.
46	Boiler Interlocks	medium	coming	Combine pressure, level, and flame inputs into a permissive output for a burner.
47	Bit Pack	easy	coming	Pack sixteen BOOL inputs into a DINT output with each input mapped to a bit.
48	Bit Unpack	easy	coming	Unpack a DINT input into sixteen BOOL outputs, one per bit position.
49	Mux 4	easy	coming	A two-bit select input chooses one of four inputs to route to the output.
50	Demux 4	easy	coming	An input is routed to one of four outputs based on a two-bit select input.
51	Encoder 8 to 3	medium	coming	Encode eight BOOL inputs as a three-bit index of the highest active input.
52	Abs Value	easy	coming	Output the absolute value of a REAL input with a separate sign flag output.
53	Modulo	easy	coming	Compute the integer modulo of two inputs with proper handling of negative dividends.
54	Stream First Above	medium	coming	Output the index of the first streamed sample to exceed a threshold.
55	Sequencer 3-Step	medium	coming	State machine stepping through Idle, Running, and Done states from Start and Reset inputs.
56	Wash Cycle	medium	coming	Four-step Fill, Mix, Drain, and Idle wash cycle with Pause, Resume, and Reset.
57	Traffic Light 2-Way	medium	coming	Drive a two-direction traffic intersection with an all-red gap between phases.
58	Pedestrian Crossing	medium	coming	Add a pedestrian-request button to a two-way traffic light without breaking the cycle.
59	Drawbridge	hard	coming	Control a drawbridge through bells, barriers, raise, and reverse with sensor-gated transitions.
60	Elevator 3-Floor	hard	coming	Control a three-floor elevator with call buttons, current floor output, and direction logic.
61	Bottle Station	hard	coming	Detect, stop, fill, cap, and eject bottles on a re-entrant station conveyor.
62	Drill Cycle	hard	coming	Two-hand-start drill cycle that descends, dwells, and retracts with a release-stops-cycle rule.
63	Recipe Batch	hard	coming	Execute a four-step recipe with per-step time and temperature parameters and a Done flag.
64	Emergency Shutdown	hard	coming	Layered shutdown with light-fault soft-stop, hard-fault hard-stop, and a chained all-stop output.
65	Streaming Sum	medium	coming	Accumulate a running total of streamed samples with a manual reset.
66	Sliding Max	medium	coming	Output the maximum of the last N streamed samples in a sliding window.
67	FIFO	medium	coming	First-in-first-out queue with Push, Pop, Out, and Full, Empty, and Count outputs.
68	LIFO	medium	coming	Last-in-first-out stack with Push, Pop, Peek, and Top, Count, and Empty outputs.
69	Ring Buffer	medium	coming	Fixed-size ring buffer with overwrite-oldest behavior and status outputs.
70	Recipe Select	medium	coming	Select one of ten recipes by index and output the selected recipe parameters.
71	Alarm History	medium	coming	Latch alarms, accept operator ack, and keep a sixteen-deep history of events.
72	Motor Bank Stats	medium	coming	Aggregate run count, fault count, and max-hours index across eight motor inputs.
73	Lookup Fixed	medium	coming	Linear interpolation through a fixed (X, Y) curve table set at design time.
74	Event Stats	medium	coming	Push events with a code and output last code, total event count, and oldest code.
75	Motor Starter	medium	coming	Motor starter with Start, Stop, Reset, and Auto inputs producing Run and Faulted outputs.
76	Conveyor Section	medium	coming	Energy-saving conveyor with upstream-edge start, downstream-edge stop, and a manual override.
77	Pump Station 3	hard	coming	Three-pump duty, standby, and standby station with run-hour rotation and fault transfer.
78	Mixer Tank	hard	coming	Combine agitator, heater, level control, and recipe time into a mixing tank controller.
79	Diverter Gate	hard	coming	Three-way conveyor diverter routed by an upstream classifier signal and a presence sensor.
80	Indexing Table	hard	coming	Rotary indexing table with Home, Step, and Fault states plus a position output.
81	Lubrication Cycle	hard	coming	Periodic lubrication pulse generator with skip-on-fault and run-condition gating.
82	Burner Control	hard	coming	Burner control state machine through Purge, Ignite, Run, and Lockout states with safety inputs.
83	Pallet Stop	hard	coming	Pallet-stop conveyor block with raise and lower cylinders, presence sensors, and escape logic.
84	Zone Controller	hard	coming	Material-flow zone controller with upstream and downstream handshake signals.
85	Parking Garage	hard	coming	Run entry and exit counters, a full sign, gate control, and capacity for a parking garage.
86	Bag Filler	hard	coming	Weigh, fill to target, reject overweight bags, and count batches on a packaging line.
87	Washing Machine	hard	coming	Programmable wash cycle: fill, agitate, drain, and spin with door interlock and fault holding.
88	Injection Molder	hard	coming	Clamp, inject, cool, and eject sequence with pressure and temperature permissives per step.
89	Railway Crossing	hard	coming	Detect approach, lower barriers, hold, and raise with a safety check at end of cycle.
90	Wastewater Station	hard	coming	Wastewater pump alternation with high-level alarm, dry-run protection, and comm-fault handling.
91	Stacker Crane	hard	coming	Run an XY stacker crane to a target slot, pick from infeed, and deliver to the bin row.
92	Batch Reactor	hard	coming	Multi-step batch reactor with operator confirms, hold-on-fault, and end-of-batch reporting.
93	Wind Turbine Yaw	hard	coming	Yaw controller aligning to wind direction with hysteresis, cable-wind protection, and override.
94	Bottling Line	hard	coming	Coordinate infeed, fill, cap, label, and palletize stations on a bottling line.
95	Alarm Shelving	medium	coming	Alarm with shelve, ack, and unshelve states plus a reactivation timer and operator inputs.
96	Mode Manager	medium	coming	Manual, Auto, SemiAuto, and Fault state manager with a mode-id output and transitions.
97	Bumpless Swap	hard	coming	Swap from manual to automatic control without a setpoint kick at the transition.
98	Deadband Plus	medium	coming	Tunable filter combining deadband, hysteresis, and rate limiting in one block.
99	Leaky Bucket	hard	coming	Rate limiter that counts pulses, drains over time, and outputs Allowed and Level.
100	First Out Fault	hard	coming	Latch the first of N fault inputs to fire and output the index with the latched flag.
101	Moving Median 3	medium	coming	Output the streaming median of the last three samples to reject outlier spikes.
102	Rate Limited Ramp	medium	coming	Track an input target but move the output no faster than a given rate per second.
103	Failover Primary	hard	coming	Primary and secondary source selector with hysteresis and per-source health flags.
104	Dual Heartbeat	hard	coming	Watchdog with two heartbeat inputs that alarms on either missing and outputs last-seen times.