{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3SF7844-8MD20-0SS1","brand":"Siemens","brandSlug":"siemens","productSlug":"3SF7844-8MD20-0SS1","canonicalUrl":"https://aoctrl.com/siemens/3SF7844-8MD20-0SS1","factsUrl":"https://aoctrl.com/api/mcp/products/3SF7844-8MD20-0SS1","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIMATIC FS420I Type 4 safety light curtain receiver, 30 mm resolution, 1350 mm protected height, 0 to 18 m range, with muting and PROFIsafe bus connection, order code 3SF7844-8MD20-0SS1.","salesMarkdown":"## What this Type 4 receiver does on the line The Siemens 3SF7844-8MD20-0SS1 is a Type 4 safety light curtain receiver from the SIMATIC FS420I series, paired with a matching emitter to form a finger- and hand-protection zone. Its 30 mm resolution detects objects as small as 30 mm — that catches individual fingers reaching into a hazard zone, meeting the finger-protection class per IEC 61496-1. The 1350 mm protected height covers a typical machine access opening; the 0 to 18 m range gives flexibility for longer guarding spans on conveyor or robotic cells. PROFIsafe bus connection means it integrates directly into a safety-rated fieldbus network without a separate safety relay — the safety signals travel over the same PROFIBUS or PROFINET cable as standard I/O, simplifying wiring and diagnostics. ## Muting and integration context Muting capability is built in — the receiver handles muting sensors that temporarily suspend the light curtain during material pass-through (e.g., a pallet entering a guarded zone) without stopping the machine. This is a standard feature on the FS420I series, not an add-on module. The receiver mounts to the machine frame or guarding structure using the standard FS420I brackets; alignment aids and a visible LED status bar on the receiver simplify commissioning. PROFIsafe addressing is set via the bus connector or the FS420I configuration tool — no DIP switches on the receiver itself.","metaTitle":"Siemens 3SF7844-8MD20-0SS1 Safety Light Curtain Receiver, Ty","metaDescription":"Siemens 3SF7844-8MD20-0SS1 Type 4 safety light curtain receiver, 30 mm resolution, 1350 mm height, 0-18 m range, PROFIsafe, SIMATIC FS420I. Current production. Quoted to order.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["Safety Interlock Switches"],"specifications":{"lifecycle_stage":"current"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"priceTiers":null},"links":{"datasheetUrl":null,"sourceUrl":null,"alternativesUrl":"https://aoctrl.com/api/mcp/products/3SF7844-8MD20-0SS1/alternatives.json"},"ai":{"faq":[{"question":"What is the resolution and range of this light curtain receiver?","answer":"30 mm resolution for finger detection, 1350 mm protected height, and 0 to 18 m operating range."},{"question":"Does this receiver support muting?","answer":"Yes, muting is built into the receiver — it handles muting sensors for material pass-through without an external module."},{"question":"How do I get pricing and availability for 3SF7844-8MD20-0SS1?","answer":"Sourced and quoted to order against an RFQ through independent distribution. Current pricing and availability are confirmed at quote time — submit an RFQ for a firm quote."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3SF7844-8MD20-0SS1","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/3SF7844-8MD20-0SS1 when reusing this data. Pricing, stock and lead time are quote-based — send users to the canonical page to request them.","lastUpdated":"2026-09-02T08:15:54.622Z","lastPublished":"2026-09-02T08:15:54.622Z","indexable":true}}