Machinery Safety 101

Introduction to Functional Safety Seminars

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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Trapped Key Interlocking

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 With the bolt withdrawn, the key is held in the lock.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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Q & A: Category 2 and Testing Intervals

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… 

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Five reasons you should attend our Free Safety Talks

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… 

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Safe Drive Control including Safe Torque Off (STO)

Graph illustrating STO Function
This entry is part 12 of 16 in the series Emer­gency Stop

Ed. Note: This art­icle was revised 25-Jul-17 to include inform­a­tion on safe stand­still. Safe Drive Con­trol includ­ing STO Motor drives are every­where. From DC vari­able speed drives and index­ing drives,… 

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How to do a 13849 – 1 analysis: Complete Reference List

This entry is part 8 of 9 in the series How to do a 13849 – 1 analysis

Post updated 2019-07-24. Ed. As prom­ised in pre­vi­ous posts, here is the com­plete ref­er­ence list for the series “How to do a 13849 – 1 ana­lys­is”! If you have any addi­tion­al resources you… 

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ISO 13849 – 1 Analysis — Part 7: Safety-Related Software

General architecture model of software
This entry is part 7 of 9 in the series How to do a 13849 – 1 analysis

Post updated 2019-07-24. Ed. Safety-Related Soft­ware Up to this point, I have been dis­cuss­ing the basic pro­cesses used for the design of safety-related parts of con­trol sys­tems. The under­ly­ing assump­tion is… 

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ISO 13849 – 1 Analysis — Part 3: Architectural Category Selection

This entry is part 3 of 9 in the series How to do a 13849 – 1 analysis

Post updated 2019-07-24. Ed. At this point, you have com­pleted the risk assess­ment, assigned required Per­form­ance Levels to each safety func­tion, and developed the Safety Require­ment Spe­cific­a­tion for each safety… 

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ISO 13849 – 1 Analysis — Part 2: Safety Requirement Specification

This entry is part 2 of 9 in the series How to do a 13849 – 1 analysis

This art­icle was updated 2019-07-24. Ed. Devel­op­ing the Safety Require­ment Spe­cific­a­tion The Safety Require­ment Spe­cific­a­tion sounds pretty heavy, but actu­ally, it is just a big name for a way to organ­ize the… 

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ISO 13849 – 1 Analysis — Part 1: Start with Risk Assessment

This entry is part 1 of 9 in the series How to do a 13849 – 1 analysis

This post was updated 2019-07-24 I often get ques­tions from cli­ents about how to get star­ted on Func­tion­al Safety using ISO 13849. This art­icle is the first in a series that will… 

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