{"id":5777,"date":"2017-01-03T13:49:30","date_gmt":"2017-01-03T12:49:30","guid":{"rendered":"http:\/\/www.gemac-fieldbus.com\/?p=5777\/"},"modified":"2025-10-27T12:48:51","modified_gmt":"2025-10-27T11:48:51","slug":"can-bus-wiring-test","status":"publish","type":"post","link":"https:\/\/alt.gemac-fieldbus.com\/en\/can-bus-wiring-test\/","title":{"rendered":"CAN bus wiring test"},"content":{"rendered":"<div id='av_section_1'  class='avia-section av-7ndqw1-c2d7faccadaa6a37d6663607ea7246dc main_color avia-section-default avia-no-shadow  avia-builder-el-0  avia-builder-el-no-sibling  avia-bg-style-scroll container_wrap sidebar_right'  ><div class='container av-section-cont-open' ><main  role=\"main\" itemprop=\"mainContentOfPage\"  class='template-page content  av-content-small alpha units'><div class='post-entry post-entry-type-page post-entry-5777'><div class='entry-content-wrapper clearfix'>\n\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-64ekw1-4ba13f5dbcbd2a8c621a038dc4489288\">\n.flex_column.av-64ekw1-4ba13f5dbcbd2a8c621a038dc4489288{\nborder-radius:0px 0px 0px 0px;\npadding:0px 0px 0px 0px;\n}\n<\/style>\n<div  class='flex_column av-64ekw1-4ba13f5dbcbd2a8c621a038dc4489288 av_two_third  avia-builder-el-1  el_before_av_one_third  avia-builder-el-first  first flex_column_div av-zero-column-padding  '     ><section  class='av_textblock_section av-jj9sudpo-967f4914231e5df1a2f8e0abbbdae97a '   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/BlogPosting\" itemprop=\"blogPost\" ><div class='avia_textblock'  itemprop=\"text\" ><h3 class=\"faq-title flush-left\">CAN bus wiring test<\/h3>\n<p>The wiring test sequence raises questions from time to time. Here we explain why the sequence is as it is. There are also a few tips.<\/p>\n<p>For the measurement, you must operate the tester with 24V.<\/p>\n<p>The sequence is as follows:<\/p>\n<h4>Preparation for step 1:<\/h4>\n<ul>\n<li>switch off the system (the bus to be measured must be voltage-free)<\/li>\n<li>The nodes must be disconnected from the bus (the input capacities could lead to errors).<\/li>\n<li>You must remove the terminations (they are measured later).<\/li>\n<li>Attach the tester at the beginning of the system.<\/li>\n<\/ul>\n<h3>Measurement 1:\u00a0short circuit test<\/h3>\n<p>The resistors of the wiring are measured. They should be infinite high because no wire is supposed to be connected to another in any way. For instance, there will be an error if you forgot to disconnect one of the termination resistors.<br \/>\nShort circuits and transfer resistance between wires sometimes occur in badly mounted plugs.<\/p>\n<h4>Preparation for step 2:<\/h4>\n<ul>\n<li>Connect a short circuit plug to the end of the bus. (In a short circuit plug, all pins are connected to each other.)<\/li>\n<\/ul>\n<h3>Measurement 2:\u00a0line-break test<\/h3>\n<p>The shorting plug connects all wires of the bus at the end of the cable. The loop impedance and the cable length are determined. Values can differ, then you should look for breaks and bad connections. If you did not disconnect some nodes, the determined length could vary. To measure short cables is not easy. The calculated length is more exact at longer cables.<\/p>\n<h4>Preparation for step 3:<\/h4>\n<ul>\n<li>disconnect the shorting plug<\/li>\n<li>connect the termination resistor at the end of the bus<\/li>\n<\/ul>\n<h3>Measurement 3:\u00a0termination resistor at the end of the bus<\/h3>\n<p>Considering\u00a0the former measured loop resistance, the termination resistor at the end is measured.<\/p>\n<h4>Preparation for step 4:<\/h4>\n<ul>\n<li>connect the termination resistor at the beginning of the bus<\/li>\n<\/ul>\n<h3>Measurement 4:\u00a0termination resistor at the beginning of the bus<\/h3>\n<p>In the last step, the termination resistor at the beginning of the bus is measured by considering the former measurements of loop resistance and the termination resistor at the end of the bus.<\/p>\n<hr \/>\n<h3>Hints<\/h3>\n<ul>\n<li>Under some circumstances, the nodes can stay connected to the bus. The calculation of the bus length will be influenced. It is possible that you get errors, for instance, when you also measure power supply wires and have a low impedance power supply connected.<\/li>\n<li>You might smooth away faults when you move many connectors. If you assume that you have loose connections, it can be better to measure with connected nodes first.<\/li>\n<li>Starting measurement 1 without doing the preparations will calculate a resistor of about 60 Ohm between CAN_H and CAN_L. This is, of course, rated as an error because, in measurement 1, very high resistors are expected. But to quickly check the 2 termination resistors, this procedure is good &#8211; even if the device rate this as an error.<br \/>\nIt will not be so easy at long trunk lines with higher loop resistance. Here it would be best if you compared it to former measurements.<\/li>\n<li>The CAN-Bus Tester 2 could be damaged if you ignore the warnings of the software and start the measurement process with a voltage applied. The CANtouch refuses the measurement as long as there is a voltage on the supply lines.<\/li>\n<\/ul>\n<\/div><\/section><\/div>\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-4dnx5t-13045e1372b2eb2a106bb1619d0fc38b\">\n.flex_column.av-4dnx5t-13045e1372b2eb2a106bb1619d0fc38b{\nborder-radius:0px 0px 0px 0px;\npadding:0px 0px 0px 0px;\n}\n<\/style>\n<div  class='flex_column av-4dnx5t-13045e1372b2eb2a106bb1619d0fc38b av_one_third  avia-builder-el-3  el_after_av_two_third  avia-builder-el-last  flex_column_div av-zero-column-padding  '     ><div  class='avia-builder-widget-area clearfix  avia-builder-el-4  avia-builder-el-no-sibling '><div id=\"rpwe_widget-3\" class=\"widget clearfix rpwe_widget recent-posts-extended\"><style>.rpwe-block ul{\r\nlist-style: none !important;\r\nmargin-left: 0 !important;\r\npadding-left: 0 !important;\r\n}\r\n\r\n.rpwe-block li{\r\nborder-bottom: 1px solid #eee;\r\nmargin-bottom: 10px;\r\npadding-bottom: 10px;\r\nlist-style-type: none;\r\n}\r\n\r\n.rpwe-block a{\r\ndisplay: inline !important;\r\ntext-decoration: none;\r\n}\r\n\r\n.rpwe-block h3{\r\nbackground: none !important;\r\nclear: none;\r\nmargin-bottom: 0 !important;\r\nmargin-top: 0 !important;\r\nfont-weight: 400;\r\nfont-size: 16px !important;\r\nline-height: 1.5em;\r\n}\r\n\r\n.rpwe-thumb{\r\nborder: 1px solid #eee !important;\r\nbox-shadow: none !important;\r\nmargin: 2px 10px 2px 0;\r\npadding: 3px !important;\r\n}\r\n\r\n.rpwe-summary{\r\nfont-size: 12px;\r\n}\r\n\r\n.rpwe-time{\r\ncolor: #bbb;\r\nfont-size: 11px;\r\n}\r\n\r\n.rpwe-comment{\r\ncolor: #bbb;\r\nfont-size: 11px;\r\npadding-left: 5px;\r\n}\r\n\r\n.rpwe-alignleft{\r\ndisplay: inline;\r\nfloat: left;\r\n}\r\n\r\n.rpwe-alignright{\r\ndisplay: inline;\r\nfloat: right;\r\n}\r\n\r\n.rpwe-aligncenter{\r\ndisplay: block;\r\nmargin-left: auto;\r\nmargin-right: auto;\r\n}\r\n\r\n.rpwe-clearfix:before,\r\n.rpwe-clearfix:after{\r\ncontent: &quot;&quot;;\r\ndisplay: table !important;\r\n}\r\n\r\n.rpwe-clearfix:after{\r\nclear: both;\r\n}\r\n\r\n.rpwe-clearfix{\r\nzoom: 1;\r\n}\r\n<\/style><h3 class=\"widgettitle\"><a href=\"https:\/\/gemac-fieldbus.com\/en\/faq\/\" title=\"Back to FAQ overview\">Back to FAQ overview<\/a><\/h3><div  class=\"rpwe-block\"><hr>\r\n<h3>More in General<\/h3><ul class=\"rpwe-ul\"><li class=\"rpwe-li rpwe-clearfix\"><h3 class=\"rpwe-title\"><a href=\"https:\/\/alt.gemac-fieldbus.com\/en\/can-bus-wiring-test\/\" target=\"_self\">CAN bus wiring test<\/a><\/h3><\/li><li class=\"rpwe-li rpwe-clearfix\"><h3 class=\"rpwe-title\"><a href=\"https:\/\/alt.gemac-fieldbus.com\/en\/can-symboleditor-manual\/\" target=\"_self\">CAN Symboleditor Manual<\/a><\/h3><\/li><li class=\"rpwe-li rpwe-clearfix\"><h3 class=\"rpwe-title\"><a href=\"https:\/\/alt.gemac-fieldbus.com\/en\/canbusview-xl-iii-can-quick-tester-c-qt15-and-devicenet-analyzer\/\" target=\"_self\">CANBUSview XL III, CAN Quick Tester C-QT15 and DeviceNet Analyzer<\/a><\/h3><\/li><li class=\"rpwe-li rpwe-clearfix\"><h3 class=\"rpwe-title\"><a href=\"https:\/\/alt.gemac-fieldbus.com\/en\/cantouch-vs-can-bus-tester-2-the-decision\/\" target=\"_self\">CANtouch vs. CAN-Bus Tester 2, the decision<\/a><\/h3><\/li><li class=\"rpwe-li rpwe-clearfix\"><h3 class=\"rpwe-title\"><a href=\"https:\/\/alt.gemac-fieldbus.com\/en\/detection-of-short-circuits-in-the-can-bus-error-patterns\/\" target=\"_self\">Detection of short circuits in the CAN bus &#8211; Error patterns<\/a><\/h3><\/li><li class=\"rpwe-li rpwe-clearfix\"><h3 class=\"rpwe-title\"><a href=\"https:\/\/alt.gemac-fieldbus.com\/en\/exchange_service\/\" target=\"_self\">Exchange service for fieldbus diagnostic devices<\/a><\/h3><\/li><li class=\"rpwe-li rpwe-clearfix\"><h3 class=\"rpwe-title\"><a href=\"https:\/\/alt.gemac-fieldbus.com\/en\/repair-complaint-customs\/\" target=\"_self\">Repair, complaint, customs<\/a><\/h3><\/li><li class=\"rpwe-li rpwe-clearfix\"><h3 class=\"rpwe-title\"><a href=\"https:\/\/alt.gemac-fieldbus.com\/en\/retaking-of-old-devices\/\" target=\"_self\">Retaking of old devices<\/a><\/h3><\/li><li class=\"rpwe-li rpwe-clearfix\"><h3 class=\"rpwe-title\"><a href=\"https:\/\/alt.gemac-fieldbus.com\/en\/suggested-bit-timing-and-bus-length\/\" target=\"_self\">Suggested bit timing and bus length<\/a><\/h3><\/li><li class=\"rpwe-li rpwe-clearfix\"><h3 class=\"rpwe-title\"><a href=\"https:\/\/alt.gemac-fieldbus.com\/en\/trunk-and-drop-line-lengths\/\" target=\"_self\">Trunk and drop line lengths<\/a><\/h3><\/li><\/ul><\/div><!-- Generated by http:\/\/wordpress.org\/plugins\/recent-posts-widget-extended\/ --><\/div><\/div><\/div><\/div><\/div><\/main><!-- close content main element --><\/div><\/div><div id='after_section_1'  class='main_color av_default_container_wrap container_wrap sidebar_right'  ><div class='container av-section-cont-open' ><div class='template-page content  av-content-small alpha units'><div class='post-entry post-entry-type-page post-entry-5777'><div class='entry-content-wrapper clearfix'>\n","protected":false},"excerpt":{"rendered":"","protected":false},"author":22,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"wds_primary_category":0,"footnotes":""},"categories":[89,92,94],"tags":[],"class_list":["post-5777","post","type-post","status-publish","format-standard","hentry","category-faq-cbt2-en","category-faq-cantouch-en","category-faq-general"],"_links":{"self":[{"href":"https:\/\/alt.gemac-fieldbus.com\/en\/wp-json\/wp\/v2\/posts\/5777","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/alt.gemac-fieldbus.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/alt.gemac-fieldbus.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/alt.gemac-fieldbus.com\/en\/wp-json\/wp\/v2\/users\/22"}],"replies":[{"embeddable":true,"href":"https:\/\/alt.gemac-fieldbus.com\/en\/wp-json\/wp\/v2\/comments?post=5777"}],"version-history":[{"count":0,"href":"https:\/\/alt.gemac-fieldbus.com\/en\/wp-json\/wp\/v2\/posts\/5777\/revisions"}],"wp:attachment":[{"href":"https:\/\/alt.gemac-fieldbus.com\/en\/wp-json\/wp\/v2\/media?parent=5777"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/alt.gemac-fieldbus.com\/en\/wp-json\/wp\/v2\/categories?post=5777"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/alt.gemac-fieldbus.com\/en\/wp-json\/wp\/v2\/tags?post=5777"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}