{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"6ES7421-1EL00-0AA0","brand":"Siemens","brandSlug":"siemens","productSlug":"6ES7421-1EL00-0AA0","canonicalUrl":"https://aoctrl.com/siemens/6ES7421-1EL00-0AA0","factsUrl":"https://aoctrl.com/api/mcp/products/6ES7421-1EL00-0AA0","rawCanonicalId":null},"summary":{"shortDescription":"Siemens 6ES7421-1EL00-0AA0 — now in phase-out and being discontinued. Supplied from remaining channel stock; full specifications, lifecycle and same-series options are below.","salesMarkdown":"## Overview The 6ES7421-1EL00-0AA0 is a Siemens SM 421 digital input module for the S7-400 system, providing 32 isolated inputs rated for 120 V AC/DC. It draws 6.5 W from the backplane and occupies a single-wide slot on the rack. Each of the 32 channels accepts a nominal signal of 120 V at 47 to 63 Hz AC, or 80 to 132 V DC, with a typical input current of 2 mA (2 to 5 mA range). The module also responds to a 0 to 20 V UC range for low-level detection. Switching current per channel is 1 mA. Isolation between channels and the backplane is tested at 1500 V, supporting reliable operation in electrically noisy environments. Status LEDs on the front panel indicate the logic state of each input for quick commissioning and fault isolation. ## Applications This SM 421 module is used in Siemens S7-400 racks for medium to large automation systems — process plants, power generation, water treatment, and factory lines — where 120 V AC/DC discrete signals from pushbuttons, limit switches, proximity sensors, or relay contacts need to be brought into the controller. Siemens has classified the 6ES7421-1EL00-0AA0 as phase-out, with a discontinuation date of 2025-10-01. After that date, the module will no longer be manufactured. Buyers should evaluate last-time-buy options or plan for a migration to a current S7-400 input module.","metaTitle":"Siemens 6ES7421-1EL00-0AA0 SM 421 Digital Input Module, 32 DI, 120 V AC/DC","metaDescription":"Siemens SM 421 digital input module 6ES7421-1EL00-0AA0: 32 isolated inputs, 120 V AC/DC, 6.5 W, phase-out as of 2025-10-01. Request quote.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"NRND","categoryPath":["Digital Input Modules"],"specifications":{"Depth":"210 mm","Width":"25 mm","Height":"290 mm","2-Wire Sensor":"Yes","For Signal \"0\"":"0 to 20 V UC","For Signal \"1\"":"79 to 132 V AC; 80 to 132 V DC","Shielded, Max.":"1 000 m","Weight, approx.":"600 g","lifecycle_stage":"mature","Power loss, typ.":"6.5 W","Rated value (UC)":"120 V; 47 ... 63 Hz","Unshielded, Max.":"600 m","At \"0\" To \"1\", Max.":"25 ms; 10 / 20 ms","At \"0\" To \"1\", Min.":"5 ms","At \"1\" To \"0\", Max.":"25 µs","At \"1\" To \"0\", Min.":"5 ms","Between The Channels":"Yes","For Signal \"0\", Min.":"0 mA","For Signal \"1\", Typ.":"2 mA; 2 to 5 mA","Isolation tested with":"1 500 V AC","Type of input voltage":"AC/DC","Number of digital inputs":"32","from backplane bus 5 V DC, max.":"200 mA","Between The Channels, In Groups Of":"8","Between The Channels And Backplane Bus":"Yes","Status indicator digital input (green)":"Yes","Input characteristic according to IEC 61131":"Type 1","Number of simultaneously controllable inputs":"32","Permissible Quiescent Current (2-Wire Sensor), Max.":"1 mA","For Signal \"0\", Max. (Permissible Quiescent Current)":"1 mA"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$518.72 – $1,373.00","stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/2f9a04072d513b8b44e7701c8153f91c.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=321722&mlfb=6ES7421-1EL00-0AA0"},"ai":{"faq":[],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/6ES7421-1EL00-0AA0","citationPolicyUrl":"https://aoctrl.com/llms.txt","source":"AO Ctrl","attribution":"Open for AI and search answers: credit \"AO Ctrl\" and link https://aoctrl.com/siemens/6ES7421-1EL00-0AA0 when reusing this data. Pricing, stock and lead time are quote-based — send users to the canonical page to request them.","lastUpdated":"2026-07-20T14:41:02.429Z","lastPublished":"2026-07-20T14:41:02.429Z","indexable":true}}