[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"doc-seo-655293-105":3,"detail-sidebar-cat-0-en-105":81,"doc-detail-655293-en":130},{"code":4,"msg":5,"data":6},0,"ok",{"site_id":7,"language":8,"slug":9,"title":10,"keywords":11,"description":12,"schema_data":13,"social_meta":74,"head_meta":76,"extra_data":78,"updated_unix":80},105,"en","iec61131-3-ladder-diagram-symbols","IEC61131-3 Ladder Diagram Symbols","","This technical reference document provides a comprehensive overview of standard symbols used in IEC 61131-3 ladder diagram programming for Programmable Logic Controllers (PLCs). It categorizes and defines essential components including normally open (NO) and normally closed (NC) contacts, transition-sensing contacts, various coil types (SET, RESET, negated, and pulse-sensing), and common industrial hardware representations such as pushbutton switches, indicator lamps, and protection devices like fuses and overload heaters. Designed as a foundational guide for automation engineers and students, the content clarifies the functional logic of power-passing symbols and cross-references common nomenclature, such as Allen-Bradley's XIC and XIO instructions. By detailing both the visual representation and the logical execution of these symbols, the document serves as an indispensable resource for developing, reading, and troubleshooting industrial ladder logic programs in professional control environments.",{"@graph":14,"@context":73},[15,34,56],{"@type":16,"itemListElement":17},"BreadcrumbList",[18,23,27,31],{"item":19,"name":20,"@type":21,"position":22},"https://docshare.wps.com","Home","ListItem",1,{"item":24,"name":25,"@type":21,"position":26},"https://docshare.wps.com/document/","Document",2,{"item":28,"name":29,"@type":21,"position":30},"https://docshare.wps.com/document/technology/","Technology",3,{"item":32,"name":10,"@type":21,"position":33},"https://docshare.wps.com/document/iec61131-3-ladder-diagram-symbols/655293/",4,{"url":32,"name":10,"@type":35,"image":36,"author":41,"headline":10,"publisher":44,"fileFormat":47,"inLanguage":8,"description":12,"dateModified":48,"datePublished":49,"encodingFormat":47,"isAccessibleForFree":50,"interactionStatistic":51},"DigitalDocument",{"url":37,"@type":38,"width":39,"height":40},"https://docshare.wps.com/thumbnails/iec61131-3-ladder-diagram-symbols/655293.png","ImageObject",300,407,{"name":42,"@type":43},"Angel","Person",{"url":19,"name":45,"@type":46},"DocShare","Organization","application/pdf","2026-11-01","2026-10-25",true,{"@type":52,"interactionType":53,"userInteractionCount":55},"InteractionCounter",{"@type":54},"ViewAction",6,{"@type":57,"mainEntity":58},"FAQPage",[59,65,69],{"name":60,"@type":61,"acceptedAnswer":62},"What is the primary function of a normally open (NO) contact in a ladder diagram?","Question",{"text":63,"@type":64},"A normally open contact passes power (ON) if the coil driving the contact is closed, often referred to as XIC (Examine If Closed) in Allen-Bradley terminology.","Answer",{"name":66,"@type":61,"acceptedAnswer":67},"How does a negated coil differ from a standard output coil?",{"text":68,"@type":64},"A negated coil outputs an inverse signal, meaning the output is OFF when the left-to-right path of inputs passes power, acting as the logical opposite of a standard OTE (Output Energize) coil.",{"name":70,"@type":61,"acceptedAnswer":71},"What common hardware components are represented by ladder symbols?",{"text":72,"@type":64},"Common hardware components include indicator lamps, heating elements, NC and NO pushbutton switches, overload heaters, and fuses.","https://schema.org",{"og:url":32,"og:type":75,"og:title":10,"og:site_name":45,"og:description":12},"article",{"robots":77,"canonical":32},"index,follow",{"doc_id":79,"site_id":7},655293,1792988252,{"code":4,"msg":82,"data":83},"success",[84,88,92,96,101,104,109,114,119,122,126],{"id":22,"doc_module":4,"doc_module_name":25,"category_name":85,"show_sort_weight":86,"slug":87},"Story & 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Spirituality",20,"religion-spirituality",{"id":117,"doc_module":4,"doc_module_name":25,"category_name":120,"show_sort_weight":117,"slug":121},"World Cup","world-cup",{"id":123,"doc_module":4,"doc_module_name":25,"category_name":124,"show_sort_weight":123,"slug":125},10,"Lifestyle","lifestyle",{"id":127,"doc_module":4,"doc_module_name":25,"category_name":128,"show_sort_weight":97,"slug":129},19,"General","general",{"code":4,"msg":82,"data":131},{"doc_id":79,"user_id":132,"nickname":42,"user_avatar":133,"doc_module":4,"category_id":55,"category_name":29,"doc_title":10,"doc_description":12,"doc_content":134,"file_id":135,"file_url":136,"file_type":137,"file_size":138,"view_count":55,"is_deleted":4,"is_public":22,"is_downloadable":22,"audit_status":22,"page_count":55,"language":139,"language_code":8,"site_id":7,"html_lang":8,"table_of_contents":140,"faqs":141,"seo_title":142,"seo_description":12,"update_tm":143,"read_time":144},687207412472,"https://ap-avatar.wpscdn.com/davatar_155a257f0dc6eb9ab79c44ca47cae57d","IEC61131-3 Ladder Diagram Symbols  \nby PLC Academy  \nPosilive Transibon-Sensing Contecl  \nNO Contacl  \nNegetlive Transitian-Sensing Conkact  \nNC Contad  \nSET Laich Coil  \nRESET Latch Coil  \nNegaled Coil  \nPosibive Transition-Sensing Coil  \nNegatve Transition-Sensing Coil  \nPasses power (ON)if coil driving the contact is(Allen-Bradley calls it XIC-eXamine If Closed   \n# Normally open contact\n\nNormally closed contact  \n/上  \nPasses power(ON)if coil driving the contact isAllen-Bradley calls it XIO-eXamine If Open  \n# Output or coil\n\n一(  )○  \nIf any left-to-right path of inputs passes power,outputAllen-Bradley calls it OTE-OuTput Energize  \n①/)  \n# Not Output or coil\n\nIf any left-to-right path of inputs passes power,output i  \nNormally Open  \n(NO)  \nNormally Closed  \n(NC)  \nCoil  \nBox  \n# NO relay contactNC relay contact\n\nIndicator lampHeating element  \nNC pushbutton switchNO pushbutton switch  \nOverload heaterFuse","cbCaij3wWnj7CViA","https://ap.wps.com/l/cbCaij3wWnj7CViA","pdf",652434,"English","# Contact Symbols\n## Coil Symbols\n## Industrial Component Symbols","[{\"question\":\"What is the primary function of a normally open (NO) contact in a ladder diagram?\",\"answer\":\"A normally open contact passes power (ON) if the coil driving the contact is closed, often referred to as XIC (Examine If Closed) in Allen-Bradley terminology.\"},{\"question\":\"How does a negated coil differ from a standard output coil?\",\"answer\":\"A negated coil outputs an inverse signal, meaning the output is OFF when the left-to-right path of inputs passes power, acting as the logical opposite of a standard OTE (Output Energize) coil.\"},{\"question\":\"What common hardware components are represented by ladder symbols?\",\"answer\":\"Common hardware components include indicator lamps, heating elements, NC and NO pushbutton switches, overload heaters, and fuses.\"}]","IEC61131-3 Ladder Diagram Symbols | PDF",1792960627,15]