Canada

More E-Stop Questions

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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 are three primary sources for the require­ments for emer­gency stop devices: [1] Safety of machinery — Emer­gency stop — Prin­ciples for design, 3rd Edi­tion. ISO 13850. 2015. [2] Safety of […]

Complementary Protective Measures

Emergency Stop Pull-Cords

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This entry is part 15 of 16 in the series Emer­gency Stop

This art­icle was updated 2019-04-26, adding spe­cif­ic details related to IEC 60947 – 5 – 5. 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 […]

Emergency Stop

Emergency Stop Failures

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This entry is part 13 of 16 in the series Emer­gency Stop

I am always look­ing for inter­est­ing examples of machinery safety prob­lems to share on MS101. Recently I was scrolling Reddit/r/OSHA and found these three real-world examples. Broken Emer­gency Stop But­tons The first and most obvi­ous kinds of fail­ures are those res­ult­ing from either wear out or dam­age to emer­gency stop devices like e-stop but­tons or pull […]

Canada

ISO 13849 – 1 Analysis — Part 6: CCF — Common Cause Failures

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This entry is part 6 of 9 in the series How to do a 13849 – 1 ana­lys­is

What is a Com­mon Cause Fail­ure? There are two sim­il­ar-sound­ing terms that people often get con­fused: Com­mon Cause Fail­ure (CCF) and Com­mon Mode Fail­ure. While these two types of fail­ures sound sim­il­ar, they are dif­fer­ent. A Com­mon Cause Fail­ure is a fail­ure in a sys­tem where two or more por­tions of the sys­tem fail at the same time from a single […]

Canada

Testing Emergency Stop Systems

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This entry is part 11 of 16 in the series Emer­gency Stop

I’ve had a num­ber of ques­tions from read­ers regard­ing test­ing of emer­gency stop sys­tems, and par­tic­u­larly with the fre­quency of test­ing. I addressed the types of tests that might be needed in anoth­er art­icle cov­er­ing Check­ing Emer­gency Stop Sys­tems. This art­icle will focus on the fre­quency of test­ing rather than the types of tests. The Prob­lem Emer­gency […]

Canada

CSA Z432 Safeguarding of Machinery – 3rd Edition

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If you build machinery for the Cana­dian mar­ket, or if you modi­fy equip­ment in Cana­dian work­places, you will be famil­i­ar with CSA Z432, Safe­guard­ing of Machinery. This stand­ard has been around since 1992, with the last major revi­sion pub­lished in 2004. CSA has recon­vened the Tech­nic­al Com­mit­tee respons­ible for this import­ant stand­ard to revise the […]

CE Mark

Emergency stop devices: the risks of installer liability

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This entry is part 10 of 16 in the series Emer­gency Stop

On the MachineBuilding.net blog today, Alex D’Arcy, Sales Dir­ect­or at Hylec-APL provides some inter­est­ing insights into the liab­il­it­ies asso­ci­ated with the install­a­tion of emer­gency stop devices on machinery. Hylec-APL provides tech­nic­al products and solu­tions in the field of indus­tri­al machinery and emer­gency stop sys­tems. Check out Alex’s art­icle. If you need to know more about the […]

Control Functions

Interlock Architectures – Pt. 5: Category 4 — Control Reliable

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This entry is part 5 of 8 in the series Cir­cuit Archi­tec­tures Explored

Ed. note: I’ve made a few updates to this art­icle since it was first pub­lished in 2011, with the most recent today, 6-Dec-18. – DN – The most reli­able of the five sys­tem archi­tec­tures, Cat­egory 4 is the only archi­tec­ture that uses mul­­tiple-fault tol­er­ant tech­niques to help ensure that com­pon­ent fail­ures do not res­ult in an unac­cept­able […]

Control Functions

Interlock Architectures – Pt. 4: Category 3 – Control Reliable

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Category 3 Architecture Logic Block Diagram
This entry is part 4 of 8 in the series Cir­cuit Archi­tec­tures Explored

Cat­egory 3 sys­tem archi­tec­ture is the first cat­egory that could be con­sidered to have sim­il­ar­ity to “Con­trol Reli­able” cir­cuits or sys­tems as defined in the North Amer­ic­an stand­ards. It is not the same as Con­trol Reli­able, but we’ll get to in a sub­sequent post. If you haven’t read the first three posts in this series, you may […]