{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3SF5811-2AA08","brand":"Siemens","brandSlug":"siemens","productSlug":"3SF5811-2AA08","canonicalUrl":"https://aoctrl.com/siemens/3SF5811-2AA08","factsUrl":"https://aoctrl.com/api/mcp/products/3SF5811-2AA08","rawCanonicalId":null},"summary":{"shortDescription":"Siemens 3SF5811-2AA08, AS-Interface emergency-stop pushbutton, F slave 2I, 22 mm mounting, IP67, metal enclosure, rotate-to-unlatch, positive-opening contacts.","salesMarkdown":"## AS-Interface Emergency-Stop with Positive-Opening Contacts The Siemens 3SF5811-2AA08 is a self-contained emergency-stop pushbutton designed for AS-Interface safety networks. It integrates an EMERGENCY-STOP mushroom pushbutton (red actuator, yellow enclosure top) with an AS-Interface F slave (type 2I), meaning it reports two input channels directly onto the AS-i bus without a separate I/O module. The positive-opening contacts (IEC 60947-5-1, clause K.2.1) mechanically force the normally-closed circuit open even if the contacts weld — this is the core safety feature for a category 0 or 1 stop per EN ISO 13850. The rotate-to-unlatch mechanism prevents accidental reset; the operator must twist the actuator to release it, which is the standard for guarded equipment restart. ## IP67 Sealing and Metal Enclosure for Washdown Environments Rated IP67, the 3SF5811-2AA08 withstands temporary immersion and hose-directed water — suitable for food-processing lines, washdown stations, or outdoor conveyor transfer points where moisture and debris are present. The metal enclosure (holder and housing) provides impact resistance in high-traffic areas where plastic could crack. The 22 mm round mounting hole is the standard industrial pilot-device cutout, so it retrofits into existing panel punches without adapter plates. Vertical fastening method is specified; the square front profile (85 mm × 85 mm) occupies a standard footprint on the enclosure surface. ## AS-Interface F Slave with Pre-Wired Termination The 3SF5811-2AA08 is an AS-Interface F slave (fail-safe slave) with two digital inputs (2I), meaning it directly connects to an AS-i safety monitor without an intermediate safety relay. The F-slave designation per AS-Interface Safety at Work (IEC 62061) supports SIL 3 / PL e architectures when paired with a compatible safety monitor. The unit ships pre-wired on a strip terminal, which simplifies field installation: no need to open the enclosure for wiring — just terminate the AS-i flat cable and the strip connector. The DC operating voltage is supplied directly from the AS-i bus (30 V DC nominal per the AS-i specification), so no separate power supply is needed for the slave electronics.","metaTitle":"Siemens 3SF5811-2AA08 AS-Interface E-Stop, IP67, 22mm","metaDescription":"Siemens 3SF5811-2AA08 emergency-stop pushbutton with AS-Interface F slave (2I). IP67, positive-opening contacts, rotate-to-unlatch. Current lifecycle stage. Sourced to order agains","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["Safety Interlock Switches"],"specifications":{"Depth":"65 mm","Width":"85 mm","Height":"85 mm","During Storage":"-40 ... +80 °C","of AS-i slaves":"Floor mounting","lifecycle_stage":"current","During Operation":"-25 ... +70 °C","Number Of Labels":"0","Positive Opening":"Yes","Product Function":"EMERGENCY-STOP","Mounting Diameter":"22 mm","at DC rated value":"30 V","protection class IP":"IP67","Design Of The Housing":"AS-Interface enclosure with standard equipment","Number Of Lampholders":"0","number of AS-i slaves":"1","EMERGENCY OFF function":"Yes","Material Of The Holder":"Metal","EMERGENCY STOP function":"Yes","Design Of The Slave Type":"F slave, 2I","Number Of Backing Plates":"0","Number Of Command Points":"1","Type Of Unlocking Device":"rotate-to-unlatch mechanism","Material Of The Enclosure":"metal","Number Of Switching Elements":"2","Product Component Front Ring":"No","Shape Of The Enclosure Front":"Square","Substance Prohibitance (Date)":"05/28/2009","Color Of The Actuating Element":"red","Product Component Light Source":"No","Color Of The Enclosure Top Part":"yellow","Design Of The Actuating Element":"EMERGENCY STOP mushroom pushbutton","Fastening Method Of The Enclosure":"Vertical","Material Of The Actuating Element":"plastic","Shape Of The Installation Opening":"round","Product Component Protective Collar":"No","Product Extension Optional Light Source":"No","reference code according to IEC 81346-2":"S","Type Of Voltage Of The Operating Voltage":"DC","Delivery State Pre-Wired On Strip Terminal":"Yes","Of Contact Blocks, Socket, And Accessories":"Floor mounting","Type Of Electrical Connection On Enclosure":"With insulation-displacement terminal, top","with low demand rate according to SN 31920":"20 %","with high demand rate according to SN 31920":"20 %","number of CO contacts for auxiliary contacts":"0","number of NC contacts for auxiliary contacts":"2","number of NO contacts for auxiliary contacts":"0","Tightening Torque Of The Screws In The Bracket":"1.4 ... 1.6 N·m","vibration resistance according to IEC 60068-2-6":"20 ... 200 Hz: 5g"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"priceTiers":null},"links":{"datasheetUrl":null,"sourceUrl":null,"alternativesUrl":"https://aoctrl.com/api/mcp/products/3SF5811-2AA08/alternatives.json"},"ai":{"faq":[{"question":"Where can I buy the 3SF5811-2AA08 and get a price?","answer":"The 3SF5811-2AA08 is sourced and quoted to order against an RFQ through independent distribution. Availability and current pricing are confirmed at quote time — submit an RFQ for a firm quote."},{"question":"What does the F slave 2I designation mean for this emergency stop?","answer":"F slave 2I means the 3SF5811-2AA08 is an AS-Interface fail-safe slave with two digital inputs. It reports the emergency-stop status directly onto the AS-i safety bus without a separate safety relay, supporting SIL 3 / PL e architectures when paired with a compatible AS-i safety monitor."},{"question":"What compliance documentation is available for the 3SF5811-2AA08?","answer":"The part carries a RoHS compliance date of 05/28/2009, covering EU Directive 2011/65/EU. The positive-opening contacts meet IEC 60947-5-1 requirements. AS-Interface F-slave certification per the AS-Interface Safety at Work profile is inherent to the design."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3SF5811-2AA08","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/3SF5811-2AA08 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}}