{"product_id":"yokogawa-alr121-s51-serial-communication-interface-module","title":"Yokogawa ALR121-S51 Serial Communication Interface Module","description":"\u003ch3 class=\"\"\u003eProduct Overview\u003c\/h3\u003e\n\u003cp\u003e\u003cspan class=\"\"\u003eThe Yokogawa ALR121-S51 is a specialized serial communication module designed to bridge the gap between Yokogawa Field Control Stations (FCS) and external subsystems.\u003c\/span\u003e\u003cspan class=\"\"\u003e\u003cspan\u003e \u003c\/span\u003ePrimarily utilized within the CENTUM VP and ProSafe-RS safety architectures,\u003c\/span\u003e\u003cspan class=\"\"\u003e\u003cspan\u003e \u003c\/span\u003ethis module facilitates the periodic collection of data from slave devices and stores them in localized I\/O image areas.\u003c\/span\u003e\u003cspan class=\"\"\u003e\u003cspan\u003e \u003c\/span\u003eThis architecture allows the DCS or SIS to access subsystem data asynchronously,\u003c\/span\u003e\u003cspan class=\"\"\u003e\u003cspan\u003e \u003c\/span\u003eensuring that control logic execution remains deterministic and unaffected by external network latency.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan class=\"\"\u003eThe ALR121-S51 is engineered for mission-critical applications where safety integrity is paramount.\u003c\/span\u003e\u003cspan class=\"\"\u003e\u003cspan\u003e \u003c\/span\u003eIt is often deployed in tandem with safety relay logic to provide SIL3-compliant communication pathways.\u003c\/span\u003e\u003cspan class=\"\"\u003e\u003cspan\u003e \u003c\/span\u003eThis makes it an ideal solution for integrating third-party PLCs,\u003c\/span\u003e\u003cspan class=\"\"\u003e\u003cspan\u003e \u003c\/span\u003eburner management systems (BMS),\u003c\/span\u003e\u003cspan class=\"\"\u003e\u003cspan\u003e \u003c\/span\u003eand emergency shutdown (ESD) subsystems into a unified Yokogawa control environment.\u003c\/span\u003e\u003c\/p\u003e\n\u003ch3 class=\"\"\u003eTechnical Specifications\u003c\/h3\u003e\n\u003cul class=\"list-paddingleft-2\"\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong class=\"\"\u003eManufacturer:\u003c\/strong\u003e\u003cspan class=\"\"\u003e\u003cspan\u003e \u003c\/span\u003eYokogawa\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong class=\"\"\u003eModel Number:\u003c\/strong\u003e\u003cspan class=\"\"\u003e\u003cspan\u003e \u003c\/span\u003eALR121-S51\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong class=\"\"\u003eCommunication Interface:\u003c\/strong\u003e\u003cspan class=\"\"\u003e\u003cspan\u003e \u003c\/span\u003eRS-422 \/ RS-485 (2-wire or 4-wire)\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong class=\"\"\u003eNumber of Ports:\u003c\/strong\u003e\u003cspan class=\"\"\u003e\u003cspan\u003e \u003c\/span\u003e2 independent serial channels\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong class=\"\"\u003eProtocol Support:\u003c\/strong\u003e\u003cspan class=\"\"\u003e\u003cspan\u003e \u003c\/span\u003eModbus RTU (Slave\/Master support depending on system configuration)\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong class=\"\"\u003eSafety Integrity Level:\u003c\/strong\u003e\u003cspan class=\"\"\u003e\u003cspan\u003e \u003c\/span\u003eSIL3 certified (when integrated into ProSafe-RS systems)\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong class=\"\"\u003eBaud Rate:\u003c\/strong\u003e\u003cspan class=\"\"\u003e\u003cspan\u003e \u003c\/span\u003eUp to 115.\u003c\/span\u003e\u003cspan class=\"\"\u003e2 kbps\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong class=\"\"\u003eMaximum Cable Length:\u003c\/strong\u003e\u003cspan class=\"\"\u003e\u003cspan\u003e \u003c\/span\u003e1200 meters (RS-422\/RS-485 standard)\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong class=\"\"\u003eIsolation:\u003c\/strong\u003e\u003cspan class=\"\"\u003e\u003cspan\u003e \u003c\/span\u003eGalvanic isolation between field side and system logic\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong class=\"\"\u003eOperating Temperature:\u003c\/strong\u003e\u003cspan class=\"\"\u003e\u003cspan\u003e \u003c\/span\u003e-20°C to +60°C\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong class=\"\"\u003eDimensions:\u003c\/strong\u003e\u003cspan class=\"\"\u003e\u003cspan\u003e \u003c\/span\u003e32.\u003c\/span\u003e\u003cspan class=\"\"\u003e8 mm x 130 mm x 140 mm\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong class=\"\"\u003eWeight:\u003c\/strong\u003e\u003cspan class=\"\"\u003e\u003cspan\u003e \u003c\/span\u003e0.\u003c\/span\u003e\u003cspan class=\"\"\u003e30 kg\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong class=\"\"\u003eOrigin:\u003c\/strong\u003e\u003cspan class=\"\"\u003e\u003cspan\u003e \u003c\/span\u003eJapan\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3 class=\"\"\u003eKey Technical Characteristics\u003c\/h3\u003e\n\u003cul class=\"list-paddingleft-2\"\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong class=\"\"\u003eAsynchronous Data Management:\u003c\/strong\u003e\u003cspan class=\"\"\u003e\u003cspan\u003e \u003c\/span\u003eBy utilizing internal I\/O image mapping,\u003c\/span\u003e\u003cspan class=\"\"\u003e\u003cspan\u003e \u003c\/span\u003ethe module allows the Field Control Station to reference subsystem data through standard function blocks without waiting for serial polling cycles to complete.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong class=\"\"\u003eSIL3 Certified Reliability:\u003c\/strong\u003e\u003cspan class=\"\"\u003e\u003cspan\u003e \u003c\/span\u003eBuilt to meet TÜV and IEC 61508 standards,\u003c\/span\u003e\u003cspan class=\"\"\u003e\u003cspan\u003e \u003c\/span\u003eensuring that communication between the safety controller and external devices maintains the highest levels of safety integrity.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong class=\"\"\u003eFail-Safe Relay Architecture:\u003c\/strong\u003e\u003cspan class=\"\"\u003e\u003cspan\u003e \u003c\/span\u003eIncorporates redundant design principles to ensure that even in the event of a partial hardware failure,\u003c\/span\u003e\u003cspan class=\"\"\u003e\u003cspan\u003e \u003c\/span\u003ethe system remains in a safe state.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong class=\"\"\u003eEnhanced Noise Immunity:\u003c\/strong\u003e\u003cspan class=\"\"\u003e\u003cspan\u003e \u003c\/span\u003eFeatures optical isolation for all serial signals,\u003c\/span\u003e\u003cspan class=\"\"\u003e\u003cspan\u003e \u003c\/span\u003eprotecting the internal system bus from ground loops and electromagnetic interference common in heavy industrial zones.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong class=\"\"\u003eFront-Panel Diagnostics:\u003c\/strong\u003e\u003cspan class=\"\"\u003e\u003cspan\u003e \u003c\/span\u003eIntegrated LED indicators provide real-time status for transmit\/receive (TX\/RX) activity and module health (RDY\/HRD),\u003c\/span\u003e\u003cspan class=\"\"\u003e\u003cspan\u003e \u003c\/span\u003esimplifying field troubleshooting.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong class=\"\"\u003eSimplified Integration:\u003c\/strong\u003e\u003cspan class=\"\"\u003e\u003cspan\u003e \u003c\/span\u003eThe module is fully recognized by Yokogawa engineering tools,\u003c\/span\u003e\u003cspan class=\"\"\u003e\u003cspan\u003e \u003c\/span\u003eallowing for easy configuration of Modbus registers and port parameters within the standard software environment.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e \u003c\/p\u003e","brand":"Yokogawa","offers":[{"title":"Default Title","offer_id":45519065022637,"sku":"ALR121-S51","price":99.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0733\/1613\/9181\/files\/yokogawa-alr121-s51-serial-communication-module-pluo4vwae0b.jpg?v=1766986049","url":"https:\/\/www.maxwellplc.com\/products\/yokogawa-alr121-s51-serial-communication-interface-module","provider":"Maxwell PLC Ltd","version":"1.0","type":"link"}