{"id":39062,"date":"2021-07-23T17:58:51","date_gmt":"2021-07-23T15:58:51","guid":{"rendered":"https:\/\/www.reersafety.cn\/?page_id=39062"},"modified":"2023-02-10T14:31:24","modified_gmt":"2023-02-10T13:31:24","slug":"overview-of-the-main-safety-requirements-and-functional-characteristics-of-the-5-categories","status":"publish","type":"page","link":"https:\/\/www.reersafety.cn\/en\/academy\/industrial-safety-guide\/iso-13849-12safety-of-machinery\/overview-of-the-main-safety-requirements-and-functional-characteristics-of-the-5-categories\/","title":{"rendered":"Overview of the main safety requirements and functional characteristics of the 5 categories"},"content":{"rendered":"\n<div class=\"row\"  id=\"row-645161753\">\n\n\n\t<div id=\"col-940147546\" class=\"col small-12 large-12\"  >\n\t\t<div class=\"col-inner\"  >\n\t\t\t\n\t\t\t\n\n  <div id=\"page-header-1685259792\" class=\"page-header-wrapper\">\n  <div class=\"page-title light simple-title\">\n\n    \n    <div class=\"page-title-inner container align-center flex-row medium-flex-wrap row-reverse\" >\n            <div class=\"title-content flex-col flex-left text-left medium-text-center\">\n        <div class=\"title-breadcrumbs pb-half pt-half\"><nav class=\"woocommerce-breadcrumb breadcrumbs uppercase\">Home<\/nav><\/div>      <\/div>\n    <\/div>\n\n       <\/div>\n    <\/div>\n  \n\n\n\t\t<\/div>\n\t\t\t<\/div>\n\n\t\n\n<\/div>\n<div class=\"row\"  id=\"row-711678040\">\n\n\n\t<div id=\"col-1060399180\" class=\"col small-12 large-12\"  >\n\t\t<div class=\"col-inner\"  >\n\t\t\t\n\t\t\t\n\n<div class=\"row\"  id=\"row-1916056824\">\n\n\n\t<div id=\"col-1402207281\" class=\"col small-12 large-12\"  >\n\t\t<div class=\"col-inner\"  >\n\t\t\t\n\t\t\t\n\n<h2>Overview of the main safety requirements and functional characteristics of the 5 categories<\/h2>\n<p>The categories reflect what is already happening in the industrial machinery world. Most of the controls implemented can be reduced to a limited number of safety control types. That means:<\/p>\n<ul>\n<li>Untested single-channel systems based on component reliability (attempt to avoid failure)<\/li>\n<li>Single-channel systems with testing (attempts to detect the fault)<\/li>\n<li>Dual-channel systems with self-diagnosis (trying to check the fault)<\/li>\n<li>Dual-channel systems with high quality self-diagnosis (even multiple faults are checked)<\/li>\n<\/ul>\n<p>NOTE: The lines and arrows in the following figures represent logical, functional, and diagnostic interconnections.<\/p>\n\t<section class=\"section\" id=\"section_346669764\">\n\t\t<div class=\"bg section-bg fill bg-fill  bg-loaded\" >\n\n\t\t\t\n\t\t\t\n\t\t\t\n\t<div class=\"is-border\"\n\t\tstyle=\"border-color:rgb(235, 235, 235);border-width:1px 0px 0px 0px;\">\n\t<\/div>\n\n\t\t<\/div>\n\n\t\t<div class=\"section-content relative\">\n\t\t\t\n\n<div class=\"row row-large align-middle align-center\"  id=\"row-1774710543\">\n\n\n\t<div id=\"col-1523337468\" class=\"col medium-6 small-12 large-6\"  >\n\t\t<div class=\"col-inner text-center\"  >\n\t\t\t\n\t\t\t\n\n\t<div id=\"text-201705269\" class=\"text cutom-ul\">\n\t\t\n\n<h2 style=\"text-align: left;\">\u200dCategory B<\/h2>\n<p style=\"text-align: left;\"><span style=\"color: #000080;\">Fault tolerance = 0<\/span><\/p>\n<ul>\n<li style=\"text-align: left;\">PLmax = b<\/li>\n<li style=\"text-align: left;\">DC = 0<\/li>\n<li style=\"text-align: left;\">MTTF<sub>D<\/sub> = from low to medium<\/li>\n<li style=\"text-align: left;\">Use of <span style=\"color: #000080;\"><strong>basic safety principles<\/strong><\/span> (components must withstand the expected <br>operating stresses)<\/li>\n<\/ul>\n<p>&nbsp;<\/p>\n\t\t\t<\/div>\n\t\n<span class=\"scroll-to\" data-label=\"Scroll to: #catB\" data-bullet=\"true\" data-link=\"#catB\" data-title=\"CategoryB\"><a name=\"catB\"><\/a><\/span>\n\n\n\t\t<\/div>\n\t\t\t<\/div>\n\n\t\n\n\t<div id=\"col-76617455\" class=\"col medium-6 small-12 large-6\"  >\n\t\t<div class=\"col-inner box-shadow-2 box-shadow-5-hover\" style=\"background-color:#fae76e;\" >\n\t\t\t\n\t\t\t\n\n\t<div class=\"img has-hover x md-x lg-x y md-y lg-y\" id=\"image_1982934892\">\n\t\t\t\t\t\t\t\t<div class=\"img-inner dark\" >\n\t\t\t<img width=\"386\" height=\"107\" src=\"https:\/\/www.reersafety.cn\/wp-content\/uploads\/2021\/07\/CAT_B-1.png\" class=\"attachment-large size-large\" alt=\"\" decoding=\"async\" loading=\"lazy\" srcset=\"https:\/\/www.reersafety.cn\/wp-content\/uploads\/2021\/07\/CAT_B-1.png 386w, https:\/\/www.reersafety.cn\/wp-content\/uploads\/2021\/07\/CAT_B-1-300x83.png 300w\" sizes=\"(max-width: 386px) 100vw, 386px\" \/>\t\t\t\t\t\t\n\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\n<style>\n#image_1982934892 {\n  width: 100%;\n}\n<\/style>\n\t<\/div>\n\t\n\n<p>Single channel without diagnostic<\/p>\n\n\t\t<\/div>\n\t\t\n<style>\n#col-76617455 > .col-inner {\n  padding: 15px 15px 15px 15px;\n}\n<\/style>\n\t<\/div>\n\n\t\n\n<\/div>\n\n\t\t<\/div>\n\n\t\t\n<style>\n#section_346669764 {\n  padding-top: 30px;\n  padding-bottom: 30px;\n  min-height: 200px;\n  background-color: rgb(236, 236, 236);\n}\n<\/style>\n\t<\/section>\n\t\n\t<div id=\"gap-1932091541\" class=\"gap-element clearfix\" style=\"display:block; height:auto;\">\n\t\t\n<style>\n#gap-1932091541 {\n  padding-top: 30px;\n}\n<\/style>\n\t<\/div>\n\t\n\n\t<section class=\"section\" id=\"section_2068099231\">\n\t\t<div class=\"bg section-bg fill bg-fill  bg-loaded\" >\n\n\t\t\t\n\t\t\t\n\t\t\t\n\t<div class=\"is-border\"\n\t\tstyle=\"border-color:rgb(235, 235, 235);border-width:1px 0px 0px 0px;\">\n\t<\/div>\n\n\t\t<\/div>\n\n\t\t<div class=\"section-content relative\">\n\t\t\t\n\n<div class=\"row row-large align-middle align-center\"  id=\"row-778019947\">\n\n\n\t<div id=\"col-718605738\" class=\"col medium-6 small-12 large-6\"  >\n\t\t<div class=\"col-inner text-center\"  >\n\t\t\t\n\t\t\t\n\n\t<div id=\"text-124059712\" class=\"text cutom-ul\">\n\t\t\n\n<h2 style=\"text-align: left;\">Category 1<\/h2>\n<p style=\"text-align: left;\"><span style=\"color: #000080;\">Fault tolerance = 0<\/span><\/p>\n<ul>\n<li style=\"text-align: left;\">PLmax = c<\/li>\n<li style=\"text-align: left;\">DC = 0<\/li>\n<li style=\"text-align: left;\">MTTF<sub>D<\/sub> = high<\/li>\n<li style=\"text-align: left;\">Use of <span style=\"color: #000080;\"><strong>basic safety principles<\/strong><\/span> and \u201c<span style=\"color: #000080;\"><strong>well tried\u201d safety principles<\/strong><\/span>; <br>Use of <span style=\"color: #000080;\"><strong>\u201cwell tried\u201d components<\/strong><\/span>; no complex components (PLC, Asic).<\/li>\n<\/ul>\n\t\t\t<\/div>\n\t\n\n\t\t<\/div>\n\t\t\t<\/div>\n\n\t\n\n\t<div id=\"col-524966436\" class=\"col medium-6 small-12 large-6\"  >\n\t\t<div class=\"col-inner box-shadow-2 box-shadow-5-hover\" style=\"background-color:#fae76e;\" >\n\t\t\t\n\t\t\t\n\n\t<div class=\"img has-hover x md-x lg-x y md-y lg-y\" id=\"image_70186818\">\n\t\t\t\t\t\t\t\t<div class=\"img-inner dark\" >\n\t\t\t<img width=\"386\" height=\"107\" src=\"https:\/\/www.reersafety.cn\/wp-content\/uploads\/2021\/07\/CAT_B-1.png\" class=\"attachment-large size-large\" alt=\"\" decoding=\"async\" loading=\"lazy\" srcset=\"https:\/\/www.reersafety.cn\/wp-content\/uploads\/2021\/07\/CAT_B-1.png 386w, https:\/\/www.reersafety.cn\/wp-content\/uploads\/2021\/07\/CAT_B-1-300x83.png 300w\" sizes=\"(max-width: 386px) 100vw, 386px\" \/>\t\t\t\t\t\t\n\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\n<style>\n#image_70186818 {\n  width: 100%;\n}\n<\/style>\n\t<\/div>\n\t\n\n<p>Single channel without diagnostic<\/p>\n\n\t\t<\/div>\n\t\t\n<style>\n#col-524966436 > .col-inner {\n  padding: 15px 15px 15px 15px;\n}\n<\/style>\n\t<\/div>\n\n\t\n\n<\/div>\n<p>NOTE: A &#8220;well tried component&#8221; is a component that has been:<br>Widely used in the past with positive results in similar applications<br>Built and verified using principles that demonstrate its suitability, reliability and robustness for safety related applications<br>The qualification of a component as well tried depends on its application. Example, a position switch with open contacts can be well tested for a machine tool and at the same time inappropriate for application in the food industry.<\/p>\n\n\t\t<\/div>\n\n\t\t\n<style>\n#section_2068099231 {\n  padding-top: 30px;\n  padding-bottom: 30px;\n  min-height: 200px;\n  background-color: rgb(236, 236, 236);\n}\n<\/style>\n\t<\/section>\n\t\n\t<div id=\"gap-1687601790\" class=\"gap-element clearfix\" style=\"display:block; height:auto;\">\n\t\t\n<style>\n#gap-1687601790 {\n  padding-top: 30px;\n}\n<\/style>\n\t<\/div>\n\t\n\n\t<section class=\"section\" id=\"section_348381710\">\n\t\t<div class=\"bg section-bg fill bg-fill  bg-loaded\" >\n\n\t\t\t\n\t\t\t\n\t\t\t\n\t<div class=\"is-border\"\n\t\tstyle=\"border-color:rgb(235, 235, 235);border-width:1px 0px 0px 0px;\">\n\t<\/div>\n\n\t\t<\/div>\n\n\t\t<div class=\"section-content relative\">\n\t\t\t\n\n<div class=\"row row-large align-middle align-center\"  id=\"row-1725837184\">\n\n\n\t<div id=\"col-1861178740\" class=\"col medium-6 small-12 large-6\"  >\n\t\t<div class=\"col-inner text-center\"  >\n\t\t\t\n\t\t\t\n\n\t<div id=\"text-115875608\" class=\"text cutom-ul\">\n\t\t\n\n<h2 style=\"text-align: left;\">Category 2<\/h2>\n<p style=\"text-align: left;\"><span style=\"color: #000080;\">Fault tolerance = 0<\/span><\/p>\n<ul>\n<li style=\"text-align: left;\">PLmax = c<\/li>\n<li style=\"text-align: left;\">DC = from low to medium<\/li>\n<li style=\"text-align: left;\">MTTF<sub>D<\/sub> = from low to medium (functional channel components only)<\/li>\n<li style=\"text-align: left;\">MTTF<sub>D<\/sub> of TE at least higher than half the MTTF<sub>D<\/sub> of the functional channel.<br>If this is not the case, the MTTF<sub>D<\/sub> channel must be downgraded.<\/li>\n<li style=\"text-align: left;\">Use of <span style=\"color: #000080;\"><strong>basic safety principles<\/strong><\/span> <br>Use of <span style=\"color: #000080;\"><strong>\u201cwell tried\u201d safety principles<\/strong><\/span><\/li>\n<\/ul>\n\t\t\t<\/div>\n\t\n\n\t\t<\/div>\n\t\t\t<\/div>\n\n\t\n\n\t<div id=\"col-416743821\" class=\"col medium-6 small-12 large-6\"  >\n\t\t<div class=\"col-inner box-shadow-2 box-shadow-5-hover\" style=\"background-color:#fae76e;\" >\n\t\t\t\n\t\t\t\n\n\t<div class=\"img has-hover x md-x lg-x y md-y lg-y\" id=\"image_389169910\">\n\t\t\t\t\t\t\t\t<div class=\"img-inner dark\" >\n\t\t\t<img width=\"386\" height=\"212\" src=\"https:\/\/www.reersafety.cn\/wp-content\/uploads\/2021\/07\/CAT_2.png\" class=\"attachment-large size-large\" alt=\"\" decoding=\"async\" loading=\"lazy\" srcset=\"https:\/\/www.reersafety.cn\/wp-content\/uploads\/2021\/07\/CAT_2.png 386w, https:\/\/www.reersafety.cn\/wp-content\/uploads\/2021\/07\/CAT_2-300x165.png 300w\" sizes=\"(max-width: 386px) 100vw, 386px\" \/>\t\t\t\t\t\t\n\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\n<style>\n#image_389169910 {\n  width: 100%;\n}\n<\/style>\n\t<\/div>\n\t\n\n<p>Single channel with diagnostic<\/p>\n\n\t\t<\/div>\n\t\t\n<style>\n#col-416743821 > .col-inner {\n  padding: 15px 15px 15px 15px;\n}\n<\/style>\n\t<\/div>\n\n\t\n\n<\/div>\n<p>The test must not create a dangerous situation (e.g increase in the response time).<br>The safety function must be tested at least during the start-up and before a dangerous condition can occur (starting a new cycle). The frequency of the functional channel test had to be at least 100 times higher than the request rate of the safety function.<\/p>\n<p>For ratios greater than 25 and less than 100 it is possible to use the PFHD values (shown in table K .1 for Cat. 2) multiplied by a factor of 1.1.<\/p>\n<div class=\"row align-middle\"  id=\"row-1572318973\">\n\n\n\t<div id=\"col-640571941\" class=\"col medium-6 small-12 large-6\"  >\n\t\t<div class=\"col-inner\"  >\n\t\t\t\n\t\t\t\n\n\t<div class=\"img has-hover x md-x lg-x y md-y lg-y\" id=\"image_1284217782\">\n\t\t\t\t\t\t\t\t<div class=\"img-inner dark\" >\n\t\t\t<img width=\"612\" height=\"194\" src=\"https:\/\/www.reersafety.cn\/wp-content\/uploads\/2021\/07\/EN_Time-CAT_2-1.png\" class=\"attachment-large size-large\" alt=\"\" decoding=\"async\" loading=\"lazy\" srcset=\"https:\/\/www.reersafety.cn\/wp-content\/uploads\/2021\/07\/EN_Time-CAT_2-1.png 612w, https:\/\/www.reersafety.cn\/wp-content\/uploads\/2021\/07\/EN_Time-CAT_2-1-300x95.png 300w, https:\/\/www.reersafety.cn\/wp-content\/uploads\/2021\/07\/EN_Time-CAT_2-1-510x162.png 510w\" sizes=\"(max-width: 612px) 100vw, 612px\" \/>\t\t\t\t\t\t\n\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\n<style>\n#image_1284217782 {\n  width: 100%;\n}\n<\/style>\n\t<\/div>\n\t\n\n\n\t\t<\/div>\n\t\t\t<\/div>\n\n\t\n\n\t<div id=\"col-2046841616\" class=\"col medium-6 small-12 large-6\"  >\n\t\t<div class=\"col-inner\"  >\n\t\t\t\n\t\t\t\n\n<p>The test can also be performed at the same time as the safety function request, but the overall time to detect the fault and to bring the machine to a safe condition (usually the machine is stopped) must be shorter than the time taken by a person to reach the dangerous point.<\/p>\n\n\t\t<\/div>\n\t\t\t<\/div>\n\n\t\n\n<\/div>\n<p>For PLr = a and up to PLr = c, when, upon detection of the fault, it is not possible to initiate a safe state (for example due to the welding of the contact in the output device), it may be sufficient that the output OTE only provides a warning signal.<br>For PL r = d, the OTE output must initiate a safe state which is maintained until the fault is cleared.<\/p>\n\n\t\t<\/div>\n\n\t\t\n<style>\n#section_348381710 {\n  padding-top: 30px;\n  padding-bottom: 30px;\n  min-height: 200px;\n  background-color: rgb(236, 236, 236);\n}\n<\/style>\n\t<\/section>\n\t\n\t<div id=\"gap-1958529791\" class=\"gap-element clearfix\" style=\"display:block; height:auto;\">\n\t\t\n<style>\n#gap-1958529791 {\n  padding-top: 30px;\n}\n<\/style>\n\t<\/div>\n\t\n\n\t<section class=\"section\" id=\"section_344795059\">\n\t\t<div class=\"bg section-bg fill bg-fill  bg-loaded\" >\n\n\t\t\t\n\t\t\t\n\t\t\t\n\t<div class=\"is-border\"\n\t\tstyle=\"border-color:rgb(235, 235, 235);border-width:1px 0px 0px 0px;\">\n\t<\/div>\n\n\t\t<\/div>\n\n\t\t<div class=\"section-content relative\">\n\t\t\t\n\n<div class=\"row row-large align-middle align-center\"  id=\"row-179804971\">\n\n\n\t<div id=\"col-1717452407\" class=\"col medium-6 small-12 large-6\"  >\n\t\t<div class=\"col-inner text-center\"  >\n\t\t\t\n\t\t\t\n\n\t<div id=\"text-622445447\" class=\"text cutom-ul\">\n\t\t\n\n<h2 style=\"text-align: left;\">Category 3<\/h2>\n<p style=\"text-align: left;\"><span style=\"color: #000080;\">Fault tolerance = 1<\/span><\/p>\n<ul>\n<li style=\"text-align: left;\">PLmax = e<\/li>\n<li style=\"text-align: left;\">DC = from low to medium<\/li>\n<li style=\"text-align: left;\">MTTF<sub>D<\/sub> = from low to medium<\/li>\n<li style=\"text-align: left;\">Use of <span style=\"color: #000080;\"><strong>basic safety principles<\/strong><\/span> <br>Use of <strong><span style=\"color: #000080;\">\u201cwell tried\u201d safety principles<\/span><\/strong><\/li>\n<\/ul>\n<p>A single fault does not lead to the loss of the safety function.<\/p>\n<p>When reasonably practicable, the single fault must be detected during or before the next safety function request.<\/p>\n<p>Not all faults can be detected. The accumulation of undetected faults leads to the loss of the safety function.<\/p>\n\t\t\n<style>\n#text-622445447 {\n  text-align: left;\n}\n<\/style>\n\t<\/div>\n\t\n\n\t\t<\/div>\n\t\t\t<\/div>\n\n\t\n\n\t<div id=\"col-1792133247\" class=\"col medium-6 small-12 large-6\"  >\n\t\t<div class=\"col-inner box-shadow-2 box-shadow-5-hover\" style=\"background-color:#fae76e;\" >\n\t\t\t\n\t\t\t\n\n\t<div class=\"img has-hover x md-x lg-x y md-y lg-y\" id=\"image_1099944423\">\n\t\t\t\t\t\t\t\t<div class=\"img-inner dark\" >\n\t\t\t<img width=\"386\" height=\"212\" src=\"https:\/\/www.reersafety.cn\/wp-content\/uploads\/2021\/07\/CAT_3-1.png\" class=\"attachment-large size-large\" alt=\"\" decoding=\"async\" loading=\"lazy\" srcset=\"https:\/\/www.reersafety.cn\/wp-content\/uploads\/2021\/07\/CAT_3-1.png 386w, https:\/\/www.reersafety.cn\/wp-content\/uploads\/2021\/07\/CAT_3-1-300x165.png 300w\" sizes=\"(max-width: 386px) 100vw, 386px\" \/>\t\t\t\t\t\t\n\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\n<style>\n#image_1099944423 {\n  width: 100%;\n}\n<\/style>\n\t<\/div>\n\t\n\n<p>Dual channel with diagnostic<\/p>\n\n\t\t<\/div>\n\t\t\n<style>\n#col-1792133247 > .col-inner {\n  padding: 15px 15px 15px 15px;\n}\n<\/style>\n\t<\/div>\n\n\t\n\n<\/div>\n\n\t\t<\/div>\n\n\t\t\n<style>\n#section_344795059 {\n  padding-top: 30px;\n  padding-bottom: 30px;\n  min-height: 200px;\n  background-color: rgb(236, 236, 236);\n}\n<\/style>\n\t<\/section>\n\t\n\t<div id=\"gap-1488042190\" class=\"gap-element clearfix\" style=\"display:block; height:auto;\">\n\t\t\n<style>\n#gap-1488042190 {\n  padding-top: 30px;\n}\n<\/style>\n\t<\/div>\n\t\n\n\t<section class=\"section\" id=\"section_505033178\">\n\t\t<div class=\"bg section-bg fill bg-fill  bg-loaded\" >\n\n\t\t\t\n\t\t\t\n\t\t\t\n\t<div class=\"is-border\"\n\t\tstyle=\"border-color:rgb(235, 235, 235);border-width:1px 0px 0px 0px;\">\n\t<\/div>\n\n\t\t<\/div>\n\n\t\t<div class=\"section-content relative\">\n\t\t\t\n\n<div class=\"row row-large align-middle align-center\"  id=\"row-932927885\">\n\n\n\t<div id=\"col-1885764133\" class=\"col medium-6 small-12 large-6\"  >\n\t\t<div class=\"col-inner text-center\"  >\n\t\t\t\n\t\t\t\n\n\t<div id=\"text-1751626412\" class=\"text cutom-ul\">\n\t\t\n\n<h2 style=\"text-align: left;\">Category 4<\/h2>\n<p style=\"text-align: left;\"><span style=\"color: #000080;\">Fault tolerance = 1<\/span><\/p>\n<ul>\n<li style=\"text-align: left;\">PLmax = e<\/li>\n<li style=\"text-align: left;\">DC = High<\/li>\n<li style=\"text-align: left;\">MTTF<sub>D<\/sub> = HIgh<\/li>\n<li style=\"text-align: left;\">Use of<span style=\"color: #000080;\"><strong> basic safety principles<br><\/strong><\/span>Use of <span style=\"color: #000080;\">\u201cwell tried\u201d safety principles<\/span><\/li>\n<\/ul>\n<p>A single fault does not lead to the loss of the safety function.<\/p>\n<p>Faults must be detected in time before the loss of safety function. For example, immediately upon their occurrence, or when the machine is turned on, or at the end of the operating cycle. If this detection is not possible, the combination of two faults must not lead to the loss of the safety function.<\/p>\n\t\t\n<style>\n#text-1751626412 {\n  text-align: left;\n}\n<\/style>\n\t<\/div>\n\t\n\n\t\t<\/div>\n\t\t\t<\/div>\n\n\t\n\n\t<div id=\"col-1560486135\" class=\"col medium-6 small-12 large-6\"  >\n\t\t<div class=\"col-inner box-shadow-2 box-shadow-5-hover\" style=\"background-color:#fae76e;\" >\n\t\t\t\n\t\t\t\n\n\t<div class=\"img has-hover x md-x lg-x y md-y lg-y\" id=\"image_2094724708\">\n\t\t\t\t\t\t\t\t<div class=\"img-inner dark\" >\n\t\t\t<img width=\"386\" height=\"212\" src=\"https:\/\/www.reersafety.cn\/wp-content\/uploads\/2021\/07\/CAT_3-1.png\" class=\"attachment-large size-large\" alt=\"\" decoding=\"async\" loading=\"lazy\" srcset=\"https:\/\/www.reersafety.cn\/wp-content\/uploads\/2021\/07\/CAT_3-1.png 386w, https:\/\/www.reersafety.cn\/wp-content\/uploads\/2021\/07\/CAT_3-1-300x165.png 300w\" sizes=\"(max-width: 386px) 100vw, 386px\" \/>\t\t\t\t\t\t\n\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\n<style>\n#image_2094724708 {\n  width: 100%;\n}\n<\/style>\n\t<\/div>\n\t\n\n<p>Dual channel with diagnostic<\/p>\n\n\t\t<\/div>\n\t\t\n<style>\n#col-1560486135 > .col-inner {\n  padding: 15px 15px 15px 15px;\n}\n<\/style>\n\t<\/div>\n\n\t\n\n<\/div>\n\n\t\t<\/div>\n\n\t\t\n<style>\n#section_505033178 {\n  padding-top: 30px;\n  padding-bottom: 30px;\n  min-height: 200px;\n  background-color: rgb(236, 236, 236);\n}\n<\/style>\n\t<\/section>\n\t\n\t<div id=\"gap-820391445\" class=\"gap-element clearfix\" style=\"display:block; height:auto;\">\n\t\t\n<style>\n#gap-820391445 {\n  padding-top: 30px;\n}\n<\/style>\n\t<\/div>\n\t\n\n<div class=\"is-divider divider clearfix\" style=\"max-width:100px;\"><\/div>\n\n<div class=\"row\"  id=\"row-35967081\">\n\n\n\t<div id=\"col-1379998946\" class=\"col medium-4 small-12 large-4\"  >\n\t\t<div class=\"col-inner\"  >\n\t\t\t\n\t\t\t\n\n\t<div class=\"ux-menu stack stack-col justify-start ux-menu--divider-solid\">\n\t\t\n\n\t<div class=\"ux-menu-link flex menu-item\">\n\t\t<a class=\"ux-menu-link__link flex\" href=\"https:\/\/www.reersafety.cn\/en\/academy\/industrial-safety-guide\/iso-13849-12safety-of-machinery\/\"  >\n\t\t\t<i class=\"ux-menu-link__icon text-center icon-angle-left\" ><\/i>\t\t\t<span class=\"ux-menu-link__text\">\n\t\t\t\tISO 13849-1,2 Safety of Machinery\t\t\t<\/span>\n\t\t<\/a>\n\t<\/div>\n\t\n\n\n\t<\/div>\n\t\n\n\t\t<\/div>\n\t\t\t<\/div>\n\n\t\n\n\t<div id=\"col-307448971\" class=\"col medium-4 small-12 large-4\"  >\n\t\t<div class=\"col-inner\"  >\n\t\t\t\n\t\t\t\n\n\n\t\t<\/div>\n\t\t\t<\/div>\n\n\t\n\n\t<div id=\"col-803514981\" class=\"col medium-4 small-12 large-4\"  >\n\t\t<div class=\"col-inner text-right\"  >\n\t\t\t\n\t\t\t\n\n\t<div class=\"ux-menu stack stack-col justify-start ux-menu--divider-solid\">\n\t\t\n\n\t<div class=\"ux-menu-link flex menu-item\">\n\t\t<a class=\"ux-menu-link__link flex\" href=\"https:\/\/www.reersafety.cn\/en\/academy\/industrial-safety-guide\/iso-13849-12safety-of-machinery\/computation-of-the-mttfd-2\/\"  >\n\t\t\t<i class=\"ux-menu-link__icon text-center icon-angle-right\" ><\/i>\t\t\t<span class=\"ux-menu-link__text\">\n\t\t\t\tComputation of the MTTFD\t\t\t<\/span>\n\t\t<\/a>\n\t<\/div>\n\t\n\n\n\t<\/div>\n\t\n\n\t\t<\/div>\n\t\t\t<\/div>\n\n\t\n\n<\/div>\n\n\t\t<\/div>\n\t\t\t<\/div>\n\n\t\n\n<\/div>\n\n\t\t<\/div>\n\t\t\t<\/div>\n\n\t\n\n<\/div>\n","protected":false},"excerpt":{"rendered":"","protected":false},"author":7,"featured_media":0,"parent":38995,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"om_disable_all_campaigns":false,"inline_featured_image":false,"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"_uf_show_specific_survey":0,"_uf_disable_surveys":false},"acf":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v20.1 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>Safety requirements and functional characteristics of the 5 categories<\/title>\n<meta name=\"description\" content=\"Most of the controls implemented can be reduced to a limited number of safety control types. 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