{"product_id":"3tk2821-2cb30-siemens-safety-relay-for-emergency-stop-circuits","title":"3TK2821-2CB30 Siemens Safety Relay for Emergency Stop Circuits","description":"\u003ch2\u003eProduct Description \/ Overview\u003c\/h2\u003e\n\u003cp\u003eThe Siemens 3TK2821‑2CB30 is a compact and reliable safety relay from the SIRIUS 3TK28 series, designed to ensure machine safety in industrial automation.\u003cbr\u003eIt monitors emergency stop buttons, protective doors, light barriers, and other safety devices for dependable hazard prevention.\u003c\/p\u003e\n\u003cp\u003eMoreover, this relay supports 24 V AC\/DC supply voltage, providing flexible operation for various control circuits.\u003cbr\u003eIt features 3 NO enabling contacts for safety outputs and 1 NC signaling contact for feedback or diagnostics.\u003c\/p\u003e\n\u003cp\u003eIn addition, start-up can be configured for automatic or manual monitored operation, allowing adaptive control in different safety setups.\u003cbr\u003eDIN rail mounting and cage clamp terminals simplify installation while maintaining a compact 22.5 mm housing for space efficiency.\u003c\/p\u003e\n\u003cp\u003eAlthough this model is discontinued, Siemens recommends 3SK1111‑2AB30 or 3SK1211‑2BB40\/3SK1211‑2BB00 as modern, compatible successors.\u003c\/p\u003e\n\u003ch2\u003eTechnical Data \/ Specifications\u003c\/h2\u003e\n\u003cp\u003eProduct Type: Safety relay basic unit\u003cbr\u003eSeries: SIRIUS 3TK28\u003cbr\u003eSupply Voltage: 24 V AC\/DC\u003cbr\u003eContacts: 3 NO enabling (instantaneous), 0 NO delayed, 1 NC signaling\u003cbr\u003eConnection Type: Cage clamp terminals\u003cbr\u003eHousing Width: 22.5 mm\u003cbr\u003eMounting: DIN rail\u003cbr\u003eProtection Class: IP20\u003cbr\u003eGross Weight: 239 g\u003cbr\u003eNet Weight: 0.24 kg\u003cbr\u003ePackaging Dimensions (L × W × H): 106.5 × 28 × 124 mm\u003cbr\u003eOperating Temperature: –25 … +60 °C\u003cbr\u003eStorage Temperature: –40 … +80 °C\u003cbr\u003eRelative Humidity: 10 … 95 %\u003cbr\u003eInstallation Altitude: Up to 2000 m\u003cbr\u003eSafety Integrity Level (SIL): Up to SIL1 as basic device, SIL3 as extension unit\u003cbr\u003ePerformance Level (PL): Up to PL e (EN ISO 13849-1)\u003cbr\u003eStandards Compliance: IEC 61508, EN ISO 13849-1, EN 62061\u003c\/p\u003e\n\u003ch2\u003eFAQ\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003eWhat supply voltage does the 3TK2821-2CB30 require?\u003c\/strong\u003e\u003cbr\u003eIt operates with 24 V AC\/DC, compatible with standard industrial safety circuits.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow many contacts does it provide?\u003c\/strong\u003e\u003cbr\u003eIt includes 3 NO enabling contacts and 1 NC signaling contact.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCan the start-up be configured?\u003c\/strong\u003e\u003cbr\u003eYes, it supports automatic or manual monitored start according to application needs.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat mounting type is used?\u003c\/strong\u003e\u003cbr\u003eDIN rail mounting allows compact and secure installation in control cabinets.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhich Siemens models are recommended as successors?\u003c\/strong\u003e\u003cbr\u003e3SK1111‑2AB30 or 3SK1211‑2BB40\/3SK1211‑2BB00 are modern, compatible replacements.\u003c\/p\u003e","brand":"Siemens","offers":[{"title":"Default Title","offer_id":43895216341091,"sku":"3TK2821-2CB30","price":400.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0583\/5246\/8067\/files\/62._2f4caa2f-30f5-4719-9983-29e28aa4a083.jpg?v=1765956650","url":"https:\/\/www.autocontrolglobal.com\/products\/3tk2821-2cb30-siemens-safety-relay-for-emergency-stop-circuits","provider":"AutoControl Global","version":"1.0","type":"link"}