{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RK3251-2AA10","brand":"Siemens","brandSlug":"siemens","productSlug":"3RK3251-2AA10","canonicalUrl":"https://aoctrl.com/siemens/3RK3251-2AA10","factsUrl":"https://aoctrl.com/api/mcp/products/3RK3251-2AA10","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS 3RK3251-2AA10 modular safety expansion module, 4/8 F-RO, EN 954-1 category 4, IP20, spring-loaded terminals, 124 x 45 x 113 mm.","salesMarkdown":"The Siemens 3RK3251-2AA10 is a SIRIUS modular safety expansion module rated for 4/8 F-RO (fail-safe relay outputs). It evaluates safety functions up to EN 954-1 category 4, meaning it can handle the highest fault-tolerant safety circuits — dual-channel, cross-monitored — for guarding applications like press brakes, robot cells, and conveyor zones where a single fault must not lose the safety function. It snaps onto standard DIN rail (35 mm), measures 124 mm deep by 45 mm wide by 113 mm tall, and uses spring-loaded terminals accepting 0.25–1.5 mm² solid or stranded wire (with or without ferrule). Category 4 per EN 954-1 is the deciding rating for safety buyers: it requires redundant architecture and continuous self-test so that a single component failure never defeats the safety function. That makes this module suitable for stop categories 0 and 1 on machinery where risk assessment demands the highest structural integrity. The 4/8 F-RO designation means four fail-safe relay output channels, each with two contacts (normally open) — effectively eight switching paths. The outputs are parameterizable, so you can configure them as delayed or immediate off, depending on the safety function (e.g., delayed drop for a controlled stop vs. immediate for an EMERGENCY OFF). Surge voltage resistance is rated at 4000 V, and insulation voltage at 300 V — this module is built for 400 VAC line environments with adequate clearance. Operating temperature spans -20 to +60 °C, with storage/transport range of -40 to +85 °C. Shock resistance of 15 g for 11 ms covers most machine vibration profiles. The spring terminals are tool-less — push in with a screwdriver to release. Wire strip length is 8–10 mm; use ferrules for stranded wire to avoid whiskers. The module is an expansion to a SIRIUS safety base unit (e.g., 3RK3... base), not a standalone controller — it extends the number of safety outputs on the same backplane bus.","metaTitle":"Siemens 3RK3251-2AA10 SIRIUS Expansion Module, 4/8 F-RO, Cat","metaDescription":"Siemens 3RK3251-2AA10 SIRIUS modular safety expansion module, 4/8 F-RO, EN 954-1 category 4, IP20, spring terminals. Sourced to order against RFQ.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"NRND","categoryPath":["Safety Relays"],"specifications":{"Depth":"124mm","Width":"45mm","title":"3RK3251-2AA10","Height":"113mm","2-Channel":"0","description":"SIRIUS, Extension module 3RK32 for modular Safety system 3RK3 4/8 F-RO, 24 V DC/2 A Can be parameterized via MSS ES 45 mm overall width Spring-type terminal Up to SIL3 (IEC 61508) Up to Performance Level E (ISO 13849-1) without connection cable","During Storage":"-40 ... +85°C","Safety-Related":"0","Single Channel":"8","Type Of Voltage":"DC","lifecycle_stage":"current","During Operation":"-20 ... +60°C","During Transport":"-40 ... +85°C","Fastening Method":"standard rail","Product Category":"Modular Safety System","Shock Resistance":"15g / 11 ms","Mounting Position":"vertical","Solid Or Stranded":"0.25 ... 1.5mm²","Monitored Start-Up":"No","Non-Safety-Related":"0","Product Brand Name":"SIRIUS","Degree Of Pollution":"3","Product Designation":"Expansion module","protection class IP":"IP20","Design Of The Product":"4/8 F-RO","EMERGENCY OFF function":"No","Parameterizable Outputs":"Yes","Safety-Related 2-Channel":"0","With Core End Processing":"0.25 ... 1.5mm²","category acc. to EN 954-1":"4","Protective Door Monitoring":"No","Evaluation: Enabling Switch":"No","Evaluation: Selector Switch":"No","Without Core End Processing":"0.25 ... 1.5mm²","Non-Safety-Related 2-Channel":"0","Type Of Electrical Connection":"spring-loaded terminals","Insulation Voltage Rated Value":"300V","For Testing Contact-Based Sensors":"0","Pressure-Sensitive Mat Monitoring":"No","Relative Humidity During Operation":"10 ... 95%","Evaluation: Two-Hand Operator Panel":"No","Surge Voltage Resistance Rated Value":"4 000V","reference code acc. to DIN EN 61346-2":"K","Touch Protection Against Electrical Shock":"finger-safe","control supply voltage 1 at DC rated value":"24V","PFHD with high demand rate acc. to EN 62061":"0.00000000721/h","electrostatic discharge acc. to IEC 61000-4-2":"4 kV contact discharge / 8 kV air discharge","performance level (PL) acc. to EN ISO 13849-1":"e","Safety Integrity Level (SIL) acc. to IEC 61508":"3","field-based interference acc. to IEC 61000-4-3":"10 V/m, 3 V/m, 1 V/m","Evaluation: Electro-Sensitive Protective Equipment":"No","Installation Altitude At Height Above Sea Level Maximum":"2 000m","Operating Range Factor Control Supply Voltage Rated Value Of Magnet Coil":"0.85 ... 1.15","Design Of The Fuse Link For Short-Circuit Protection Of Non-Solid-State Switching Element Required":"NH Typ 3NA, DIAZED Typ 5SB, NEOZED Typ 5SE"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$446.91","stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/0011d49d8aba42d254ba557030db59cd.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=279496&mlfb=3RK3251-2AA10"},"ai":{"faq":[{"question":"Where can I buy the 3RK3251-2AA10?","answer":"This part 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 price and lead time."},{"question":"What is the 3RK3251-2AA10 used for?","answer":"It is a fail-safe relay output expansion module for SIRIUS modular safety systems. It provides 4/8 F-RO channels for safety functions up to EN 954-1 category 4, typically used in machine guarding, press safety, and conveyor zone control."},{"question":"Does the 3RK3251-2AA10 replace a Siemens 6ES7513-1AL01-0AB0?","answer":"No — those are SIMATIC S7-1500 CPUs, a different product family entirely. The 3RK3251-2AA10 is a safety expansion module for the SIRIUS modular safety system, not a PLC. They are not electrically or mechanically interchangeable."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RK3251-2AA10","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/3RK3251-2AA10 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}}