Hardware literacy for PLC people
Industrial automation components you can see, open and operate.
Learn what the hardware around a PLC does through recognition-grade images, animated internal mechanisms, field terminals, faults and PLC-connected labs—without assuming you already know the equipment.
No install. No credit card. Immediate feedback.
Common field-device question
How do you test an industrial limit switch?
Isolate the circuit according to site procedure, identify COM, NO and NC from the actual device diagram, then measure continuity while operating the lever through its full travel. The contact should transfer cleanly and repeatably. After reconnecting, compare the physical switch, PLC input LED and tag state while the machine is in an approved test condition.
Open the animated limit-switch lesson- 01Make the machine safe and identify the actual contact diagram.
- 02Measure COM–NC and COM–NO with the actuator released.
- 03Operate the lever and confirm the contacts transfer without chatter.
- 04Inspect roller, lever, mounting and overtravel for mechanical damage.
- 05Reconnect and compare device motion, input LED and PLC tag state.
The core machine cabinet
Eight components every learner should recognise
Control hardwarePRO LABMotor Contactor
An electrically controlled heavy-duty switch. A small control voltage pulls in a magnetic mechanism that connects power to a motor or heater.
Open the cutaway
Machine safetyPRO LABEmergency-Stop Pushbutton
A red latching mushroom button used to stop hazardous motion in an emergency. Pressing it opens monitored safety contacts and it stays pressed until deliberately reset.
Open the cutaway
Motor protectionPRO LABThermal Overload Relay
A motor-protection device that watches sustained current. Too much current heats internal strips, trips the mechanism, and opens the contactor control circuit before the motor overheats.
Open the cutaway
Control hardwarePRO LAB3-Wire Motor Starter
A classic start/stop control circuit. A momentary START button pulls in the contactor, its own auxiliary contact keeps it on, and STOP breaks that holding path.
Open the cutaway
Control hardwarePRO LABIndustrial Control Relay
A small electromagnetic switch for control signals. Energising its coil changes several electrically isolated contacts at the same time.
Open the cutaway
Motor drivesPRO LABVariable Frequency Drive
An electronic motor controller that turns fixed mains power into adjustable-frequency power so an AC motor can run at different speeds.
Open the cutaway
PneumaticsPRO LABPneumatic Solenoid Valve
An electrically shifted air valve. A PLC output energises a coil, the internal spool moves, and compressed air is routed to one side of an actuator.
Open the cutaway
PneumaticsPRO LABDouble-Acting Pneumatic Cylinder
A linear air-powered actuator. Compressed air pushes a piston to extend or retract a rod that moves part of a machine.
Open the cutawayThe complete signal path
How industrial components work together around a PLC
A component makes more sense when you can place it in the control loop. Follow the chain below, then open a device lesson to inspect the mechanism, terminals, failure modes and related PLC exercise.
- 01
Command or measurement
A pushbutton, selector or sensor turns a physical condition into an electrical signal.
- 02
PLC decision
The controller reads its inputs, executes the program and decides which outputs should change.
- 03
Interface and protection
Relays, contactors, overloads and safety devices make the command suitable—and safe—for real equipment.
- 04
Machine action
A motor, VFD, valve or cylinder turns the electrical output into speed, pressure or movement.
- 05
Proof and diagnosis
Auxiliary contacts and end sensors tell the PLC whether the physical result matched the command.
Read before you wire
Field guides for the high-risk details
The interactive lesson teaches recognition and cause-and-effect. The companion field guide handles the deeper wiring, selection, protection and commissioning questions that should not be compressed into a simulator panel.
Motor Contactor
Read the guide Detailed field guideThermal Overload Relay
Read the guide Detailed field guide3-Wire Motor Starter
Read the guide Detailed field guideIndustrial Control Relay
Read the guide Detailed field guideVariable Frequency Drive
Read the guide Detailed field guidePneumatic Solenoid Valve
Read the guide Detailed field guideDouble-Acting Pneumatic Cylinder
Read the guidePlain-English answers
Industrial component questions
Which industrial automation components should a beginner learn first?
Start with pushbuttons and sensors, then learn relays, contactors and overload protection before moving to VFDs and pneumatic valves. That order follows the real signal path from an input, through the PLC, to a controlled load.
Is a contactor the same as a relay?
Both use a coil to change contacts, but a contactor is designed to switch higher-power loads such as three-phase motors. A control relay normally switches smaller control signals and provides isolation or extra contacts.
Does a PLC power a motor or pneumatic cylinder directly?
Usually not. A PLC output commands an interface device such as a contactor, VFD or solenoid valve. That device handles the motor power or compressed air while feedback returns to PLC inputs.
Can these labs replace manufacturer manuals or safety validation?
No. The labs teach recognition, signal flow, control logic and diagnosis. Real equipment selection, wiring, guarding and safety validation must follow the manufacturer documentation and the standards that apply to the machine.
Free first success
See the control loop come alive
Run the Switch & Light lab first, get a visible success, then continue into components, sensors and complete machine scenarios with your progress saved.