Category: Control Functions

This cat­egory dis­cusses vari­ous aspects of con­trol func­tions.

Emergency Stop Pull-Cords

This entry is part 14 of 14 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 com­mon emer­gency stop device is the pull-cord, and like the light-cur­tain in safe­guard­ing, the pull-cord is prob­ably the most mis­ap­plied emer­gency stop device. Con­tin­ue read­ing “Emer­gency Stop Pull-Cords”

Trapped Key Interlocking

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 a way to inter­lock guards that is equally effect­ive, and often more appro­pri­ate in dif­fi­cult envir­on­ment­al con­di­tions. Con­tin­ue read­ing “Trapped Key Inter­lock­ing”

Q & A: Category 2 and Testing Intervals

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. In the short video below, Doug answers that ques­tion.

If you have more ques­tions or felt some­thing wasn’t clear in the video, leave us a com­ment and we will get back to you!

If you are hav­ing prob­lems with devel­op­ing your safety func­tion, please get in touch with Doug dir­ectly.

Notes

Email Doug dir­ectly.

References

[1]     Safety of machinery — Safety-related parts of con­trol sys­tems — Part 1: Gen­er­al prin­ciples for design. ISO 13849 – 1. 2015.

[2]     “The Bathtub Curve and Product Fail­ure Beha­vi­or (Part 2 of 2)”, Weibull.com, 2018. [Online]. Avail­able: http://www.weibull.com/hotwire/issue22/hottopics22.htm. [Accessed: 13- May- 2018].

[3]    Ger­man Social Acci­dent Insur­ance (DGUV) – Insti­tute for Occu­pa­tion­al Safety and Health (BGIA), “Func­tion­al safety of machine con­trols — Applic­a­tion of ISO 13849 – 1 — Report 2/2008e”, Insti­tute for Occu­pa­tion­al Safety and Health (BGIA), Sankt Augustin, DE, 2008.

[4]     “Safety Cir­cuit Examples of Safety Com­pon­ents | Tech­nic­al Guide | Aus­tralia | Omron IA”, Omron.com.au, 2018. [Online]. Avail­able: http://www.omron.com.au/service_support/technical_guide/safety_component/safety_circuit_example.asp. [Accessed: 14- May- 2018].

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