{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3SK1120-2AB40","brand":"Siemens","brandSlug":"siemens","productSlug":"3SK1120-2AB40","canonicalUrl":"https://aoctrl.com/siemens/3SK1120-2AB40","factsUrl":"https://aoctrl.com/api/mcp/products/3SK1120-2AB40","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS safety relay, 3SK1120-2AB40, SIL 3 / PL e, 24 V DC, push-in spring terminals, 17.5 mm wide, screw and snap-on mounting.","salesMarkdown":"## Safety relay for guarding circuits — SIL 3 / PL e The Siemens 3SK1120-2AB40 is a SIRIUS safety relay with solid-state enabling circuits, rated for 24 V DC. It carries SIL 3 per IEC 61508 and PL e per ISO 13849-1, meaning it's certified for safety functions up to the highest performance level used in machine guarding, emergency stop, and light-curtain circuits. The 17.5 mm width and screw-and-snap-on mounting fit standard DIN-rail enclosures — a common panel footprint for a single safety function. The 24 V DC rated supply is the standard control voltage for most safety PLCs and I/O blocks — no separate power supply needed if your cabinet already runs 24 V. The push-in spring terminals (spring-loaded, no tool required for ferruled wire) accept 0.5 to 1.5 mm² stranded without ferrule, or 0.5 to 1.0 mm² with ferrule. That covers the typical field-wiring range for safety inputs and feedback loops. Start input and feedback input are both present on this unit, so you can wire a two-hand control station or monitor external contactors directly. The sensor input minimum off-time is 60 ms, which sets the minimum pulse duration the relay will recognize — relevant when using light curtains with short dark periods. Depth is 121.6 mm — verify clearance to the gland plate or door, especially in shallow cabinets. Power loss is 2 W maximum, negligible for thermal budgeting inside a ventilated panel. Shock resistance is 10 g / 11 ms, suitable for machine-mounted enclosures on presses or conveyors.","metaTitle":"Siemens 3SK1120-2AB40 SIRIUS Safety Relay, SIL 3 / PL e, 24","metaDescription":"Siemens 3SK1120-2AB40 SIRIUS safety relay, SIL 3 per IEC 61508, PL e per ISO 13849-1. Rated 24 V, push-in terminals, 17.5 mm wide. Active production. Sourced to order against RFQ.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["Safety Relays"],"specifications":{"Depth":"121.6 mm","Solid":"1x (20 ... 16), 2x (20 ... 16)","Width":"17.5 mm","at DC":"0.8 ... 1.2","Height":"100 mm","Maximum":"85 ms","Typical":"6 500 ms","Stranded":"1x (20 ... 16), 2x (20 ... 16)","Rated Value":"24 V","Start Input":"Yes","Safety Switch":"Yes","at DC maximum":"85 ms","During Storage":"-40 ... +80 °C","Feedback Input":"Yes","lifecycle_stage":"current","During Operation":"-25 ... +60 °C","Fastening Method":"screw and snap-on mounting","Product Category":"Safety relays","Shock Resistance":"10g / 11 ms","Mounting Position":"any","Product Brand Name":"SIRIUS","Degree Of Pollution":"3","Product Designation":"safety relays","Overvoltage Category":"3","Design Of The Product":"Solid-state enabling circuits","Instantaneous Contact":"1","according to IEC 61508":"3","according to IEC 62061":"3","power loss [W] maximum":"2 W","Design Of The Cascading":"yes","Safety-Related Circuits":"Yes","EMC emitted interference":"IEC 60947-5-1, Class A","With Core End Processing":"1x (0.5 ... 1.0 mm²), 2x (0.5 ... 1.0 mm²)","according to ISO 13849-1":"e","Of The Sensor Input Minimum":"60 ms","Operating Frequency Maximum":"2 000 1/h","Safe failure fraction (SFF)":"99 %","Without Core End Processing":"1x (0.5 ... 1.5 mm²), 2x (0.5 ... 1.5 mm²)","Type Of Electrical Connection":"spring-loaded terminal (push-in)","Insulation Voltage Rated Value":"50 V","Monitoring Of Floating Sensors":"Yes","Product Function Parameterizable":"sensor floating / sensor non-floating, monitored start-up / automatic start, 1-channel / 2-channel sensor connection, cross-circuit detection, startup testing, antivalent sensors, 2-hand switches","Safety-Related Delayed Switching":"0","Monitoring Of Non-Floating Sensors":"Yes","Relative Humidity During Operation":"10 ... 95 %","air pressure according to SN 31205":"90 ... 106 kPa","of the ON pushbutton input minimum":"0.15 s","Product Feature Cross-Circuit-Proof":"Yes","Cascading Input/Functional Switching":"Yes","Safety-Related Instantaneous Contact":"0","Surge Voltage Resistance Rated Value":"800 V","category according to EN ISO 13849-1":"4","protection class IP of the enclosure":"IP20","stop category according to EN 60204-1":"0","installation environment regarding EMC":"This product is suitable for Class A environments only. In household environments, this device can cause unwanted radio interference. The user is required to implement appropriate measures in this case.","Magnetically Operated Switch Monitoring":"Yes","reference code according to IEC 81346-2":"F","Recovery Time After Power Failure Typical":"6.5 s","Suitability For Interaction Press Control":"Yes","Touch Protection Against Electrical Shock":"finger-safe","of semiconductor outputs at DC-13 at 24 V":"0.5 A","safety device type according to IEC 61508-2":"Type B","Type Of Electrical Connection Plug-In Socket":"No","Type Of Voltage Of The Control Supply Voltage":"DC","Number Of Sensor Inputs 1-Channel Or 2-Channel":"1","Required Spacing For Grounded Parts At The Side":"5 mm","Type Of The Safety-Related Wiring Of The Inputs":"single-channel and two-channel","hardware fault tolerance according to IEC 61508":"1","vibration resistance according to IEC 60068-2-6":"5 ... 500 Hz: 0.75 mm","PFHD with high demand rate according to EN 62061":"1.3E-9 1/h","suitability for operation device connector 3ZY12":"Yes","PFDavg with low demand rate according to IEC 61508":"7E-6","Installation Altitude At Height Above Sea Level Maximum":"4 000 m; Derating, see Product Notification 109792701","Recovery Time After Opening Of The Safety Circuits Typical":"30 ms","Backslide Delay Time After Opening Of The Safety Circuits Typical":"40 ms","design of the fuse link for short-circuit protection of the NO contacts of the relay outputs required":"not required"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"priceTiers":null},"links":{"datasheetUrl":null,"sourceUrl":null,"alternativesUrl":"https://aoctrl.com/api/mcp/products/3SK1120-2AB40/alternatives.json"},"ai":{"faq":[{"question":"How do I get pricing and availability for 3SK1120-2AB40?","answer":"Pricing and availability are confirmed at quote time against an RFQ through independent distribution channels. Submit an RFQ for current lead times and per-unit pricing."},{"question":"What SIL / PL rating does 3SK1120-2AB40 carry?","answer":"SIL 3 per IEC 61508 and PL e per ISO 13849-1, the highest performance level for safety functions in machine guarding applications."},{"question":"What wire sizes fit the push-in terminals on 3SK1120-2AB40?","answer":"Spring-loaded push-in terminals accept 0.5 to 1.5 mm² stranded without ferrule, or 0.5 to 1.0 mm² with ferrule. Solid wire range is 1x (20 to 16 AWG) or 2x (20 to 16 AWG)."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3SK1120-2AB40","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/3SK1120-2AB40 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}}