Machinery Safety 101 » e-stop

Interlock Architectures – Pt. 4: Category 3 — Control Reliable

Doug Nix — Mon, 19 Sep 2011 12:30:13 +0000

Category 3 system architecture is the first category that could be considered to have similarity to “Control Reliable” circuits or systems as defined in the North American standards. It is not the same as Control Reliable, but we’ll get to …

Updates to Popular Articles

Doug Nix — Tue, 15 Mar 2011 16:52:37 +0000

We’ve recently updated a couple of our popular articles! Check them out! Busting Emergency Stop Myths Reader Question: Multiple E-Stops and Resets

Reader Question: Multiple E-Stops and Resets

Doug Nix — Tue, 01 Mar 2011 21:53:17 +0000

I had an interesting question come in from a reader today that is relevant to many situations: “When you have multiple E-Stop buttons I have often gotten into an argument that says you can have a reset beside each one. …

Understanding Risk Assessment

Doug Nix — Mon, 31 Jan 2011 13:30:25 +0000

When people discuss ‘Risk’ there are a lot of different assumptions made about what that means. For me, the study of risk and risk assessment techniques started in 1995. As a technologist and controls designer, I had to somehow wrap …

Emergency Stop Categories

Doug Nix — Mon, 27 Sep 2010 12:30:49 +0000

I’ve noticed a lot of people looking for information on Emergency Stop categories recently, so this post is aimed at those readers who want to understand this topic in more depth. Categories The first point to make is that these …

Busting Emergency Stop Myths

Doug Nix — Fri, 03 Sep 2010 13:30:40 +0000

There are a number of myths that have grown up around emergency stops over the years. These myths can lead to injury or death, so it's time for a little Myth Busting here on the MS101 blog!

Guarding Emergency Stop Devices

Doug Nix — Fri, 03 Sep 2010 12:30:55 +0000

Can emergency stop devices that a prone to unintended operation be guarded? Find out!

Interlock Architectures – Pt. 3: Category 2

Doug Nix — Tue, 24 Aug 2010 13:23:15 +0000

This article explores the requirements for safety related control systems meeting ISO 13849-1 Category 2 requirements. "Gotcha!" points in the definition are highlighted to help designers avoid this common pitfalls.

Interlock Architectures – Pt. 2: Category 1

Doug Nix — Wed, 28 Jul 2010 12:30:20 +0000

This article expands on the first in the series "Interlock Architectures – Pt. 1: What do those categories really mean?". Learn about the basic circuit architectures that underlie all safety interlock systems under ISO 13849-1, and CSA Z432 and ANSI RIA R15.06.

Emergency Stop — What’s so confusing about that?

Doug Nix — Fri, 06 Mar 2009 14:00:54 +0000

I get a lot of calls and emails asking about emergency stops. This is one of those deceptively simple concepts that has managed to get very complicated over time. Not every machine needs or can benefit from an emergency stop. In some cases, it may lead to an unreasonable expectation of safety from the user, which can lead to injury if they don't understand the hazards involved. Some product-specific standards