🛑 Hardwired Logic Masterclass: Start/Stop, Permissives & Safety Circuits 🧲 Ep. 32 - Chap. 10 Wrap-Up

Описание: 🧩 Why do the smartest industrial panels rely on simple relays instead of complex software? In this Chapter 10 wrap-up, we finalize your hardwired control toolbox. We break down the "Core Pattern" of industrial safety: The Start/Stop Seal-In circuit combined with Permissives, Trips, and Emergency Stops.

We explain why you should never use a "Normally Open" contact for a trip, how to wire an Emergency Stop that actually kills power (instead of just asking a PLC nicely), and the control power hygiene that prevents mystery failures.

In this lesson:
0:00 Intro: Why Software Isn't Enough
0:42 Start/Stop + Seal-In Logic Explained
1:07 The Core Pattern: Stop, Overload, Permissives, Start
1:39 NO vs NC: The Safety-Critical Rule
2:02 Latched Trips with Manual Reset (No PLC needed)
2:36 Emergency Stops: Dropping Control Power Safely
3:06 Control Power Hygiene: Fusing & Grounding
3:30 Tagging Coils: Normally Energized vs De-Energized
3:50 Mini-Case: Solar Field Permissives Logic
4:08 Trip Sources: Overload & Vibration
4:28 Commissioning Checklist: Meter Every Device
5:05 Common Mistakes: The Broken Wire Trap
5:37 History Nugget: Before PLCs, Relays Ruled

The Field Checklist:

Meter Every Device: Confirm NO/NC state at rest.

Simulate Permissives: Prove the diagram matches reality.

Trip the Overload: Verify immediate dropout.

Pull the E-Stop: Confirm coils de-energize and cannot restart.

Defeat the Logic: Open a wire and ensure the system fails Safe.

Resources:

Free Textbook (ModEL): http://ibiblio.org/kuphaldt/socratic/...

Join the Community:   / 1725422904737541  

About Crash Course Instrumentation: Hosted by an experienced I&E Instructor, we bridge the gap between textbook theory and real-world refinery maintenance. New videos every Mon/Wed/Fri at 6am PST.

Hashtags: #ElectricalSafety #StartStop #RelayLogic #IndustrialAutomation #EmergencyStop #PLC #Instrumentation