{"id":20266,"date":"2026-10-28T14:34:38","date_gmt":"2026-10-28T06:34:38","guid":{"rendered":"https:\/\/www.wehopower.com\/news\/io-link-class-a-b-power-budget-us-ua\/"},"modified":"2026-10-28T14:34:38","modified_gmt":"2026-10-28T06:34:38","slug":"io-link-class-a-b-power-budget-us-ua","status":"publish","type":"news","link":"https:\/\/www.wehopower.com\/pt\/news\/io-link-class-a-b-power-budget-us-ua\/","title":{"rendered":"IO-Link Class A and B Power Budget: Check Port Limits, US and UA"},"content":{"rendered":"<div class=\"weho-geo-content weho-geo03\">\n<p class=\"lead\"><strong>Size an IO-Link installation from three budgets: the upstream supply, the master\u2019s input groups and each individual port.<\/strong> Map system and actuator power using the exact master and device manuals, then check simultaneous current, voltage at the devices and the required behavior when one group loses power. A larger 24 V power supply cannot increase a master\u2019s port or group limit.<\/p>\n<figure id=\"figure-product-hero\" class=\"product-hero\"><a href=\"https:\/\/www.wehopower.com\/pt\/product\/ndr-dinrail-240w-ac-to-dc-single-output-switching-power-supply\/\" aria-label=\"View WEHO NDR-240 product details\"><img fetchpriority=\"high\" decoding=\"async\" src=\"https:\/\/www.wehopower.com\/wp-content\/uploads\/2026\/10\/product-scene-1.jpg\" width=\"1254\" height=\"1254\" alt=\"IO-Link Class A and B Power Budget: Check Port Limits, US and UA  title=\" io-link class and power budget: check port us ua title =\"\"><\/a><figcaption><a href=\"https:\/\/www.wehopower.com\/pt\/product\/ndr-dinrail-240w-ac-to-dc-single-output-switching-power-supply\/\">WEHO NDR-240-24<\/a> product reference in an existing AI-assisted environment. The unconnected bench scene does not demonstrate an IO-Link installation, a permitted US\/UA arrangement or functional safety. <a href=\"https:\/\/www.wehopower.com\/wp-content\/uploads\/2026\/10\/product-scene-1.jpg\">View full-size image<\/a>.<\/figcaption><\/figure>\n<p>This guide helps an equipment engineer build a power worksheet before ordering the supply and master. It is not an IO-Link communication tutorial. The useful output is a traceable port-and-group record, including the states that the machine must survive.<\/p>\n<nav class=\"toc\" aria-label=\"Table of contents\"><strong>In this guide<\/strong><\/p>\n<ol>\n<li><a href=\"#map\">Map system and actuator power<\/a><\/li>\n<li><a href=\"#limits\">Read port and group limits separately<\/a><\/li>\n<li><a href=\"#example\">Check an illustrative simultaneous-load budget<\/a><\/li>\n<li><a href=\"#states\">Define the power-loss states<\/a><\/li>\n<li><a href=\"#source\">Qualify the source and distribution<\/a><\/li>\n<li><a href=\"#handoff\">Send a complete power worksheet<\/a><\/li>\n<\/ol>\n<\/nav>\n<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_86 counter-hierarchy ez-toc-counter ez-toc-grey ez-toc-container-direction\">\n<div class=\"ez-toc-title-container\">\n<p class=\"ez-toc-title\" style=\"cursor:inherit\">\u00cdndice<\/p>\n<span class=\"ez-toc-title-toggle\"><a href=\"#\" class=\"ez-toc-pull-right ez-toc-btn ez-toc-btn-xs ez-toc-btn-default ez-toc-toggle\" aria-label=\"Alternar \u00edndice de conte\u00fado\"><span class=\"ez-toc-js-icon-con\"><span class=\"\"><span class=\"eztoc-hide\" style=\"display:none;\">Alternar<\/span><span class=\"ez-toc-icon-toggle-span\"><svg style=\"fill: #999;color:#999\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" class=\"list-377408\" width=\"20px\" height=\"20px\" viewbox=\"0 0 24 24\" fill=\"none\"><path d=\"M6 6H4v2h2V6zm14 0H8v2h12V6zM4 11h2v2H4v-2zm16 0H8v2h12v-2zM4 16h2v2H4v-2zm16 0H8v2h12v-2z\" fill=\"currentColor\"><\/path><\/svg><svg style=\"fill: #999;color:#999\" class=\"arrow-unsorted-368013\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"10px\" height=\"10px\" viewbox=\"0 0 24 24\" version=\"1.2\" baseprofile=\"tiny\"><path d=\"M18.2 9.3l-6.2-6.3-6.2 6.3c-.2.2-.3.4-.3.7s.1.5.3.7c.2.2.4.3.7.3h11c.3 0 .5-.1.7-.3.2-.2.3-.5.3-.7s-.1-.5-.3-.7zM5.8 14.7l6.2 6.3 6.2-6.3c.2-.2.3-.5.3-.7s-.1-.5-.3-.7c-.2-.2-.4-.3-.7-.3h-11c-.3 0-.5.1-.7.3-.2.2-.3.5-.3.7s.1.5.3.7z\"\/><\/svg><\/span><\/span><\/span><\/a><\/span><\/div>\n<nav><ul class='ez-toc-list ez-toc-list-level-1' ><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/www.wehopower.com\/pt\/news\/io-link-class-a-b-power-budget-us-ua\/#Map_system_and_actuator_power\" >Map system and actuator power<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/www.wehopower.com\/pt\/news\/io-link-class-a-b-power-budget-us-ua\/#Read_port_and_group_limits_separately\" >Read port and group limits separately<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/www.wehopower.com\/pt\/news\/io-link-class-a-b-power-budget-us-ua\/#Check_an_illustrative_simultaneous-load_budget\" >Check an illustrative simultaneous-load budget<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-4\" href=\"https:\/\/www.wehopower.com\/pt\/news\/io-link-class-a-b-power-budget-us-ua\/#Define_the_power-loss_states\" >Define the power-loss states<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-5\" href=\"https:\/\/www.wehopower.com\/pt\/news\/io-link-class-a-b-power-budget-us-ua\/#Qualify_the_source_and_distribution\" >Qualify the source and distribution<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-6\" href=\"https:\/\/www.wehopower.com\/pt\/news\/io-link-class-a-b-power-budget-us-ua\/#Send_a_complete_power_worksheet\" >Send a complete power worksheet<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-7\" href=\"https:\/\/www.wehopower.com\/pt\/news\/io-link-class-a-b-power-budget-us-ua\/#Discuss_the_24_V_supply_requirement_with_WEHO\" >Discuss the 24 V supply requirement with WEHO<\/a><\/li><\/ul><\/nav><\/div>\n<h2 id=\"map\"><span class=\"ez-toc-section\" id=\"Map_system_and_actuator_power\"><\/span>Map system and actuator power<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>Class A and Class B describe different IO-Link port power arrangements. <a href=\"https:\/\/www.ifm.com\/us\/en\/shared\/technologies\/io-link\/technology\/technology\" target=\"_blank\" rel=\"noopener\">ifm\u2019s explanation of A and B ports<\/a> distinguishes the usual device supply from additional power used by higher-demand output devices. Its particular product current examples must not become universal limits.<\/p>\n<p>List what each connection actually supplies: master electronics, device electronics, sensors connected through an I\/O module, actuator outputs and any loop-through feed to another master. Names such as <strong>US<\/strong> e <strong>UA<\/strong> are useful when the manufacturer defines them, but they are not a substitute for that model\u2019s power diagram.<\/p>\n<p>For a design using the Class B interface in <a href=\"https:\/\/io-link.com\/fileadmin\/user_upload\/Downloads\/Package_2024\/IOL-Interface-Spec_10002_V114_Jun24.pdf\" target=\"_blank\" rel=\"noopener\">IO-Link Interface and System Specification V1.1.4, \u00a75.4.2<\/a>, review its Power 1\/Power 2 isolation and power-loss requirements together with the declared master\/device configuration. Do not join returns or assume isolation merely because two terminals have different supply names. Check each connected device\u2019s documented isolation and return paths in the intended configuration, and resolve any conflict with the required Power 1\/Power 2 separation before connection.<\/p>\n<figure id=\"figure-technical\"><a href=\"https:\/\/www.wehopower.com\/wp-content\/uploads\/2026\/10\/technical-1.svg\" aria-label=\"Open the three-level IO-Link power budget diagram\"><picture><source media=\"(max-width:560px)\" srcset=\"https:\/\/www.wehopower.com\/wp-content\/uploads\/2026\/10\/technical-mobile-1.svg\" width=\"700\" height=\"900\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.wehopower.com\/wp-content\/uploads\/2026\/10\/technical-1.svg\" width=\"1200\" height=\"520\" alt=\"IO-Link Class A and B Power Budget: Check Port Limits, US and UA  title=\" io-link class and power budget: check port us ua title =\"\"><\/picture><\/a><figcaption>Passing one level does not prove the others. This worksheet structure is not a pinout or an approved US\/UA connection diagram. <a href=\"https:\/\/www.wehopower.com\/wp-content\/uploads\/2026\/10\/technical-1.svg\">View full-size diagram<\/a>.<\/figcaption><\/figure>\n<h2 id=\"limits\"><span class=\"ez-toc-section\" id=\"Read_port_and_group_limits_separately\"><\/span>Read port and group limits separately<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>A device may be within its own port limit while several devices exceed a shared group limit. Supply and loop-through connectors can add another constraint. Record each limit with its temperature, connector and configuration conditions. Check whether the manufacturer\u2019s stated input consumption already includes the field loads, so the worksheet neither omits nor double-counts them.<\/p>\n<p>For example, <a href=\"https:\/\/www.ifm.com\/gb\/en\/product\/AL1400\" target=\"_blank\" rel=\"noopener\">ifm\u2019s AL1400 product data<\/a> separates actuator-supply total current from per-port current and lists configurable port limiting. That layout demonstrates why one headline current number is insufficient. The values and settings for that model are not ratings for every IO-Link master.<\/p>\n<p class=\"table-hint\">On small screens, scroll sideways to read all three budget levels.<\/p>\n<div class=\"table-scroll\" tabindex=\"0\" role=\"region\" aria-label=\"IO-Link power budget levels\">\n<table>\n<thead>\n<tr>\n<th>Budget level<\/th>\n<th>Record from the exact documentation<\/th>\n<th>Decision it controls<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Upstream source<\/td>\n<td>Usable output at cabinet conditions, current-limit behavior and allowed distribution.<\/td>\n<td>Whether the source can support the intended operating events.<\/td>\n<\/tr>\n<tr>\n<td>Master input\/group<\/td>\n<td>Electronics demand, field-load total, connector and loop-through limits.<\/td>\n<td>Whether the shared path supports concurrent ports and downstream modules.<\/td>\n<\/tr>\n<tr>\n<td>Each port<\/td>\n<td>Configured limit, device running\/startup current and cable conditions.<\/td>\n<td>Whether one device may be connected and started on that port.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<h2 id=\"example\"><span class=\"ez-toc-section\" id=\"Check_an_illustrative_simultaneous-load_budget\"><\/span>Check an illustrative simultaneous-load budget<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>The following is a <strong>hypothetical 24 V worksheet<\/strong>, not an NDR rating or an approved master configuration. Assume 0.20 A for master electronics and four sensors at 0.12 A each on the system-power group. The system-group subtotal is <code>0.20 + 4 \u00d7 0.12 = 0.68 A<\/code>, before any other loads or distribution losses.<\/p>\n<p>Separately, assume three actuators each draw 0.60 A while holding and 1.50 A during pickup. Suppose the selected configuration permits 2.00 A per relevant port and 4.00 A for the actuator group. Holding demand is <code>3 \u00d7 0.60 = 1.80 A<\/code>, while concurrent pickup is <code>3 \u00d7 1.50 = 4.50 A<\/code>.<\/p>\n<p>Each 1.50 A pickup is below the assumed 2.00 A port limit, but 4.50 A exceeds the assumed 4.00 A group limit. Installing a source with a higher current rating does not remove that restriction. Review another documented configuration or a permitted operating sequence with the equipment designer. If timing is used, include overlaps, restart and fault recovery rather than assuming the normal sequence always applies.<\/p>\n<p>At nominal 24 V, the illustrative actuator group represents 43.2 W holding and 108 W during the stated pickup event. Those powers describe the example load; they do not determine source transient capability, allowable duration or isolation architecture. Retain the current-versus-time requirements beside the arithmetic.<\/p>\n<h2 id=\"states\"><span class=\"ez-toc-section\" id=\"Define_the_power-loss_states\"><\/span>Define the power-loss states<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>Write the expected behavior with system power present and actuator power removed, then with the reverse condition, both removed and each restored. Identify communication availability, the validity of sensor data, output behavior and the required restart sequence. A link that continues communicating does not prove that every attached sensor remains powered.<\/p>\n<p><a href=\"https:\/\/www.ifm.com\/ca\/en\/shared\/io-link\/products\/modules\" target=\"_blank\" rel=\"noopener\">ifm\u2019s IO-Link module guidance<\/a> specifically warns that some B-port-powered modules supply their sensors from UA along with actuators. Removing UA can therefore remove those sensors too. Review the actual module\u2019s power arrangement instead of applying the expectation from a different product.<\/p>\n<p class=\"table-hint\">On small screens, scroll sideways to compare the required power-loss behavior.<\/p>\n<div class=\"table-scroll\" tabindex=\"0\" role=\"region\" aria-label=\"IO-Link power loss and recovery record\">\n<table>\n<thead>\n<tr>\n<th>State<\/th>\n<th>Questions for the selected equipment<\/th>\n<th>Evidence to retain<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>System on, actuator off<\/td>\n<td>Which electronics and sensors remain powered? What diagnostics remain valid?<\/td>\n<td>Manual power paths and observed communication\/data behavior.<\/td>\n<\/tr>\n<tr>\n<td>System off, actuator on<\/td>\n<td>What output state is permitted? Can another interface backfeed?<\/td>\n<td>Manufacturer restrictions and defined machine response.<\/td>\n<\/tr>\n<tr>\n<td>Both off<\/td>\n<td>What energy or signals can remain at interfaces?<\/td>\n<td>Equipment power-down and maintenance requirements.<\/td>\n<\/tr>\n<tr>\n<td>Power restored<\/td>\n<td>What starts first, and can several outputs demand current together?<\/td>\n<td>Controlled restart sequence and voltage\/current records.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<p>This is a functional integration record. Separating supply groups alone does not establish a safety function or a safety rating. Any required protective shutdown needs the appropriate system design and verification.<\/p>\n<h2 id=\"source\"><span class=\"ez-toc-section\" id=\"Qualify_the_source_and_distribution\"><\/span>Qualify the source and distribution<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>After the port and group checks, assess the upstream supply at the actual installation temperature and load profile. Compare voltage at the supply, master input and relevant device during the same event. Include cable and connector drop, distribution protection and any permitted daisy chain. A nominal voltage measured at an unloaded supply does not qualify the remote port.<\/p>\n<figure id=\"figure-product-detail\" class=\"product-detail\"><a href=\"https:\/\/www.wehopower.com\/pt\/product\/ndr-dinrail-240w-ac-to-dc-single-output-switching-power-supply\/\" aria-label=\"View WEHO NDR-240 product details\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.wehopower.com\/wp-content\/uploads\/2026\/10\/product-original-1.jpg\" width=\"1000\" height=\"1000\" alt=\"IO-Link Class A and B Power Budget: Check Port Limits, US and UA  title=\" io-link class and power budget: check port us ua title =\"\"><\/a><figcaption>The exact <a href=\"https:\/\/www.wehopower.com\/pt\/product\/ndr-dinrail-240w-ac-to-dc-single-output-switching-power-supply\/\">NDR-240 - 24 (em ingl\u00eas)<\/a> identity is a starting point for requesting current supply documentation. The photo does not establish an IO-Link-compatible power architecture or safety classification. <a href=\"https:\/\/www.wehopower.com\/wp-content\/uploads\/2026\/10\/product-original-1.jpg\">View original product photo<\/a>.<\/figcaption><\/figure>\n<p>The broader <a href=\"https:\/\/www.wehopower.com\/pt\/news\/24v-power-supply-for-automation-separate-plc-sensor-and-solenoid-demand\/\">PLC, sensor and solenoid load-budget guide<\/a> covers machine branches. Here, preserve the additional master and per-port constraints. A failure at one of those levels needs a targeted correction rather than a larger supply selected without explanation.<\/p>\n<h2 id=\"handoff\"><span class=\"ez-toc-section\" id=\"Send_a_complete_power_worksheet\"><\/span>Send a complete power worksheet<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>Keep one row per connected device, its assigned port\/group, documented steady and starting current, simultaneous-event assumptions and acceptable device-terminal voltage. Add the exact master configuration, source revision and the loss-state table. Mark a missing limit as a question for the supplier, not as spare capacity.<\/p>\n<aside class=\"article-cta\">\n<h2><span class=\"ez-toc-section\" id=\"Discuss_the_24_V_supply_requirement_with_WEHO\"><\/span>Discuss the 24 V supply requirement with WEHO<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>Send the master model and configuration, port-by-port load worksheet, defined system\/actuator power arrangement, cable conditions and startup events. Ask for the source documentation needed to evaluate that configuration.<\/p>\n<p><a class=\"button\" href=\"https:\/\/www.wehopower.com\/pt\/contact\/\">Send your IO-Link power worksheet<\/a><\/aside>\n<\/div>","protected":false},"excerpt":{"rendered":"<p>Build an IO-Link power worksheet for Class A\/B ports: check US\/UA mapping, simultaneous current, group limits and behavior when power is lost.<\/p>","protected":false},"author":2,"featured_media":20235,"parent":0,"menu_order":97,"comment_status":"","ping_status":"","template":"","format":"standard","meta":{"_acf_changed":false,"_joinchat":[],"footnotes":""},"news_category":[284],"class_list":["post-20266","news","type-news","status-publish","format-standard","has-post-thumbnail","hentry","news_category-product-articles","entry"],"acf":[],"post_mailing_queue_ids":[],"_links":{"self":[{"href":"https:\/\/www.wehopower.com\/pt\/wp-json\/wp\/v2\/news\/20266","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.wehopower.com\/pt\/wp-json\/wp\/v2\/news"}],"about":[{"href":"https:\/\/www.wehopower.com\/pt\/wp-json\/wp\/v2\/types\/news"}],"author":[{"embeddable":true,"href":"https:\/\/www.wehopower.com\/pt\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.wehopower.com\/pt\/wp-json\/wp\/v2\/comments?post=20266"}],"version-history":[{"count":0,"href":"https:\/\/www.wehopower.com\/pt\/wp-json\/wp\/v2\/news\/20266\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.wehopower.com\/pt\/wp-json\/wp\/v2\/media\/20235"}],"wp:attachment":[{"href":"https:\/\/www.wehopower.com\/pt\/wp-json\/wp\/v2\/media?parent=20266"}],"wp:term":[{"taxonomy":"news_category","embeddable":true,"href":"https:\/\/www.wehopower.com\/pt\/wp-json\/wp\/v2\/news_category?post=20266"}],"curies":[{"name":"wp ent\u00e3o","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}