Machinery Safety 101
28 October, 2019

Using Form C relays in safety circuits

by Doug Nix
in Control Functions, Control Reliability, Functional Safety /
2 Comments

I recently had a dis­cus­sion with a col­league who wanted to know if it was OK for a design to include a form C relay in an e‑stop cir­cuit. You might recall that e‑stop functions… 

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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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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

When it comes to emer­gency stop devices there is no doubt that the red mush­­room-head push but­ton is the most com­mon – they seem to be every­where. The second most… 

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