Machinery Safety 101
12 July, 2021

Understanding Safety Functions: the Safety-related stop function

by Doug Nix
in Complementary Protective Measures, Control Functions, Emergency Stop, Functional Safety, Interlocks, Interlocks, ISO 13849
A stop sign - A red octagon with a white border, and white block text reading STOP.
This entry is part of 3 in the series Under­stand­ing Safety Functions

The most used safety func­tion on machinery is the safety-related stop func­tion. The require­ments dis­cussed in this post are not gen­er­ally applic­able to pro­­cess-related stop func­tions unless the pro­cess and… 

Read More
4 April, 2019

Introduction to Functional Safety Seminars

by Doug Nix
in Complementary Protective Measures, Control Functions, Emergency Stop, Events, Free Talks, Functional Safety, Guards and Guarding, Interlocks, Interlocks, ISO 13849, Seminars, Standards, Training
Man training a group of people, pointing to Functional Safety topics on the whiteboard

If you are inter­ested in func­tion­al safety, and I know many read­ers are based on the stat­ist­ics I see for my oth­er func­tion­al safety-related posts, I think you will be inter­ested in this.… 

Read More
3 July, 2018

Trapped Key Interlocking

by Doug Nix
in Control Functions, Functional Safety, Hazardous Energy Control Procedures, Interlocks, Interlocks /
6 Comments
This is a trapped key interlock on the door of an electrical switchgear cabinet. To open the door the key must be inserted and turned to withdraw a bolt that holds the door closed. With the bolt withdrawn, the key is held in the lock. The upstream switching device is held open by another interlock using the same key; since the key can only be in one of the two locks, it prevents accidentally closing the upstream switch while the cabinet is open for maintenance. The interlock is attached to the door with one-way screws to discourage casual removal of the lock, which would defeat the system.
This entry is part 3 of 7 in the series Guards and Guarding

Many machine design­ers think of inter­locks as exclus­ively elec­tric­al devices; a switch is attached to a mov­able mech­an­ic­al guard, and the switch is con­nec­ted to the con­trol sys­tem. Trapped Key Inter­lock­ing is… 

Read More
16 May, 2018

Q & A: Category 2 and Testing Intervals

by Doug Nix
in Control Functions, Functional Safety, Interlocks, ISO 13849, Q & A /
6 Comments
Logical block diagram for ISO 13849-1 Category 2 architecture.
This entry is part 1 of 2 in the series Q&A

Dur­ing the Free Safety Talks that we did with Schmersal Canada and Frank­lin Empire, we had a “hot ques­tion” come up regard­ing Cat­egory 2 archi­tec­ture and the test­ing inter­val require­ment. The… 

Read More
15 May, 2018

Five reasons you should attend our Free Safety Talks

by Doug Nix
in Events, Free Talks, Functional Safety, Hazardous Energy Control Procedures, Interlocks, Interlocks, ISO 13849, Lockout, News, Ontario, Pre-Start Health and Safety Reviews, Standards
Banner for the Free Safety Talks

Reas­on #1 – Free Safety Talks You can­’t argue with Free Stuff! Last week we partnered with Schmersal Canada and Frank­lin Empire to put on three days of Free Safety… 

Read More
All original content on these pages is fingerprinted and certified by Digiprove