What you will be able to do
- You can explain the risk-assessment idea and the order of preference for reducing risk.
- You can trace an E-stop or light-curtain stop through a safety relay to the contactors, and say why it is hard-wired and normally closed.
- You can sort the steps of a lockout/tagout procedure and explain why each one exists.
- You can describe shock, arc flash and the approach-boundary concepts, and why de-energising comes first.
- You can say what Performance Levels and SIL mean, and what dual channel with diagnostics adds, without claiming a design is certified.
- You can follow a safe pre-power and commissioning sequence and review PLC code for fail-safe behaviour.
- 01
Why machines are guarded
Free12 min · lessonAssess a jammed conveyor nip point for severity and likelihood, learn the design-out, guard, inform order, and rank six hazards.
- 02
E-stop circuits
Free15 min · lessonTrace one E-stop press from button to motor, learn stop categories 0, 1 and 2, why buttons carry two channels, and what a reset does.
- 03
Lab: dual-channel E-stop into a safety relay
Free14 min · labLand both E-stop contacts on their own relay inputs, add a reset button, and put the relay output in a contactor coil path.
- 04
Safety relays and light curtains
Pro16 min · lessonFollow a beam break through two OSSD outputs and a safety relay to the contactors, and learn what the relay checks and what a curtain cannot do.
- 05
Lab: light curtain OSSD pair into a safety relay
Pro16 min · labWire a curtain's two OSSD outputs to separate relay channels, add a start/reset button and drive two contactors from the two output contacts.
- 06
Lockout/tagout
Free16 min · lessonWork through a conveyor belt change under lockout, then sort the steps of the procedure idea, including proving a meter before testing for zero energy.
- 07
Electrical hazards
Pro14 min · lessonDecide whether a cabinet job can be done dead, then meet shock, arc flash, the NFPA 70E approach boundaries and the role of PPE.
- 08
Performance levels and SIL, introduced
Pro16 min · lessonCompare a one-switch gate with a dual-channel gate that checks itself, then match the vocabulary of PL, SIL, diagnostic coverage and common cause failure.
- 09
Machine guarding and interlocks
Pro15 min · lessonChoose between fixed guards, interlocked gates with guard locking, two-hand control and presence-sensing devices, with links to the two-hand practice scenarios.
- 10
Safe PLC programming practices
Pro14 min · lessonReview a start/stop rung for wiring polarity, feedback watchdogs and fault latching, and learn why a standard PLC is not a safety system.
- 11
Pre-power and commissioning safety checks
Pro15 min · lessonWalk the first morning on a new machine, from drawings and dead tests to safety function tests before motion, and sort the checks into a safe order.
- 12
Industrial safety knowledge check
Pro12 min · quizTen graded questions with explanations that revisit risk, stops, relays, isolation, performance levels, guarding and PLC practice.
2 of the units are graded or interactive practice on simulated equipment rather than reading:
- Lab: dual-channel E-stop into a safety relay: Land both E-stop contacts on their own relay inputs, add a reset button, and put the relay output in a contactor coil path.
- Lab: light curtain OSSD pair into a safety relay: Wire a curtain's two OSSD outputs to separate relay channels, add a start/reset button and drive two contactors from the two output contacts.
Who this track is for
Technicians, apprentices and controls engineers who work on or near machinery and need to understand the safety side of the equipment they touch.
4 of the 12 units are free with a free account, with no card and no expiry. The other 8 are part of a paid plan; compare them on the pricing page.
Related tracks
- Electrical FoundationsThe electrics you need before PLC wiring: Ohm's law to a start/stop circuit, in 12 short units.12 units, 4 free
- TroubleshootingA repeatable way to find faults: measure before you replace, halve the circuit, and read what the LEDs, the program and the meter are each telling you.27 units, 7 free
What is the difference between an E-stop and a safety relay?
The emergency stop is the operator device. A safety relay or safety controller is the monitored logic that reads that device and removes the hazardous energy in a defined, checked way. Wiring an E-stop into ordinary PLC logic alone does not give the same assurance.
Does this training certify me for lockout/tagout or arc-flash work?
No. It teaches the ideas so you recognise them on site. Qualification comes from your employer, the applicable standards and local regulation. Training material. Follow your site procedures, local electrical code and the manufacturer instructions. Lockout/tagout and a qualified person are required for real equipment.
Which safety standards does the track refer to?
It refers to them by name and purpose only, for example IEC 60204-1 for machine electrical equipment, ISO 13849-1 for safety-related control functions and NFPA 70E for electrical safety in the workplace. Always read the current edition and the rules that apply in your jurisdiction.
How much of Industrial Safety is free?
4 of the 12 units are free with a free account, no credit card and no expiry, starting with Why machines are guarded. The remaining 8 units are included with a paid plan; see the pricing page for the current plans.
Do I need a PLC or any hardware?
No. Everything runs in the browser against simulated equipment. It is training material: it does not replace supervised practice on real equipment, and lockout/tagout and a qualified person are required for real equipment.
Start with the free units
Browser-based, no install, no hardware.
Start free: Why machines are guarded