Machinery Safety 101
25 April, 2019

More E‑Stop Questions

by Doug Nix
in Canada, Control Functions, Emergency Stop, EU European Union, Standards, USA /
10 Comments
This entry is part 17 of 16 in the series Emer­gency Stop

Here are some more ques­tions I’ve been asked regard­ing emer­gency stop require­ments. These ones came to me through the IEEE PSES EMC-PSTC Product Com­pli­ance For­um mail­ing list. Primary Sources There… 

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20 April, 2019

Can Emergency Stop be used as an “on/off” control?

by Doug Nix
in Complementary Protective Measures, Control Functions, Emergency Stop, Functional Safety /
4 Comments
Emergency Stop Button
This entry is part 16 of 16 in the series Emer­gency Stop

Every couple of months I get an email ask­ing me if there is any reas­on why e‑stop func­tions can­’t be used as the primary power con­trol (on/off but­ton) for machinery. Following… 

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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.… 

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31 January, 2019

1,000,000

by Doug Nix
in News
1 Million Views!

1,000,000 views! Today marks a fant­ast­ic mile­stone for the Machinery Safety 101 blog – 1,000,000 views! When I star­ted writ­ing this blog back in Octo­ber 2008, I had high hopes that a few dozens,… 

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2 January, 2019

Do-It-Yourself Safety Labels, Signs and Tags

by Doug Nix
in Hazard Warnings
Safety label on a roller conveyor
This entry is part 1 of 5 in the series Hier­archy of Controls

One of the great chal­lenges that all product design­ers face is the sourcing of appro­pri­ate product safety labels. There are many sources for off-the-shelf labels includ­ing some of the biggest… 

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28 August, 2018

Emergency Stop Pull-Cords

by Doug Nix
in Complementary Protective Measures, Emergency Stop /
2 Comments
This entry is part 15 of 16 in the series Emer­gency Stop

This art­icle was updated 2020-06-13, adding links to the Rock­well Auto­ma­tion and Schmersal pull-cord data, and on 2019-04-26, adding spe­cif­ic details related to IEC 60947 – 5‑5 [7]. Addi­tion­al vendor links and… 

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21 August, 2018

5 Things You Need to Know About ANSI

by Doug Nix
in Standards, USA

Have you ever wondered about ANSI? Needed to know how ANSI stand­ards are developed? Find your answers and more in this post!

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10 July, 2018

Are You Ready? WEEE Directive Full Implementation Starts 15-Aug-18

by Doug Nix
in EU European Union, Uncategorized /
1 Comment
Processing of waste electrical and electronic materials

image: Advanced Recyc­ling Machines Many man­u­fac­tur­ers selling indus­tri­al products into the EU mar­ket have come to under­stand at least one of the envir­on­ment­al pro­tec­tion Dir­ect­ives, RoHS – the “Restric­tion of… 

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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… 

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7 June, 2018

How to Apply a Safety Edge to a Machine Guard – Part 3: Stopping Performance

by Doug Nix
in Guards and Guarding, Hierarchy of Controls, Safeguarding Devices /
1 Comment
CNC machine with sliding doors and safety edges
This entry is part 7 of 7 in the series Guards and Guarding

In Part 2 of this art­icle, I looked at the pres­sure-sens­it­ive devices (safety edges) them­selves. This part explores the stop­ping per­form­ance require­ments that engin­eers and tech­no­lo­gists need to con­sider when apply­ing these… 

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