{"product_id":"yokogawa-alr121-s51-s1-centum-vp-serial-communication-module","title":"Yokogawa ALR121-S51 S1 CENTUM VP Serial Communication Module","description":"\u003ch3\u003eProduct Description\u003c\/h3\u003e\n\u003cp\u003eThe\u003cspan\u003e \u003c\/span\u003e\u003cstrong\u003eALR121-S51 S1\u003c\/strong\u003e\u003cspan\u003e \u003c\/span\u003eis a high-reliability serial communication interface module designed for integration with Yokogawa CENTUM VP and Yokogawa CENTUM CS 3000 Distributed Control Systems (DCS). It acts as a communication bridge between the Field Control Station (FCS) and external industrial devices such as PLC networks, power monitoring systems, and motor controllers.\u003c\/p\u003e\n\u003cp\u003eThe module supports both\u003cspan\u003e \u003c\/span\u003e\u003cstrong\u003eRS-422 and RS-485\u003c\/strong\u003e\u003cspan\u003e \u003c\/span\u003ephysical layers, enabling flexible network topologies including point-to-point and multi-drop bus configurations.\u003c\/p\u003e\n\u003cp\u003eEngineered in Japan for long-term reliability, the ALR121-S51 S1 features\u003cspan\u003e \u003c\/span\u003e\u003cstrong\u003easynchronous half-duplex communication\u003c\/strong\u003e, electrical isolation to prevent ground loop interference, and high-density installation compatibility within Yokogawa node units. Its\u003cspan\u003e \u003c\/span\u003e\u003cstrong\u003ehot-swappable design\u003c\/strong\u003e\u003cspan\u003e \u003c\/span\u003eallows maintenance without disrupting primary control operations.\u003c\/p\u003e\n\u003chr\u003e\n\u003ch3\u003eTechnical Specifications\u003c\/h3\u003e\n\u003ctable\u003e\n\u003cthead\u003e\n\u003ctr class=\"firstRow\"\u003e\n\u003cth\u003eParameter\u003c\/th\u003e\n\u003cth\u003eSpecification\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eModel\u003c\/td\u003e\n\u003ctd\u003eALR121-S51 S1\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCommunication Interface\u003c\/td\u003e\n\u003ctd\u003eDual RS-422 \/ RS-485 ports\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTransmission Mode\u003c\/td\u003e\n\u003ctd\u003eAsynchronous, half-duplex\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBaud Rate\u003c\/td\u003e\n\u003ctd\u003e1200 – 38400 bps\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMaximum Cable Distance\u003c\/td\u003e\n\u003ctd\u003e1200 m (total bus length)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eData Format\u003c\/td\u003e\n\u003ctd\u003e7 or 8 data bits\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eStop Bits\u003c\/td\u003e\n\u003ctd\u003e1 or 2\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eError Checking\u003c\/td\u003e\n\u003ctd\u003eNone \/ Even \/ Odd parity\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eProtocol Support\u003c\/td\u003e\n\u003ctd\u003eModbus-RTU, proprietary subsystem protocols\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOperating Current\u003c\/td\u003e\n\u003ctd\u003e0.5 A at 5V DC (internal bus)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eDimensions\u003c\/td\u003e\n\u003ctd\u003e77 × 42 × 106 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eWeight\u003c\/td\u003e\n\u003ctd\u003e0.2 kg\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003chr\u003e\n\u003ch3\u003eApplication\u003c\/h3\u003e\n\u003cp\u003eThe ALR121-S51 S1 is widely used in industrial monitoring and control systems such as:\u003c\/p\u003e\n\u003cul class=\"list-paddingleft-2\"\u003e\n\u003cli\u003e\n\u003cp\u003eEnergy management systems\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eWater treatment plant automation\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eVariable Frequency Drive (VFD) monitoring\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eIndustrial sensor telemetry networks\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eIt is commonly used to connect Yokogawa controllers to third-party devices requiring\u003cspan\u003e \u003c\/span\u003e\u003cstrong\u003eModbus-RTU communication\u003c\/strong\u003e\u003cspan\u003e \u003c\/span\u003efor real-time data acquisition and control.\u003c\/p\u003e\n\u003chr\u003e\n\u003ch3\u003eFAQ\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eQ1: What is the difference between S51 and S53 variants?\u003c\/strong\u003e\u003cbr\u003eThe S51 variant represents standard CENTUM VP specifications, while S53 may indicate specialized environmental protection coatings or legacy hardware revisions.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eQ2: Does this module support redundancy?\u003c\/strong\u003e\u003cbr\u003eYes. When installed in redundant node units, two ALR121-S51 S1 modules can operate in failover configurations to ensure communication continuity.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eQ3: Can communication parameters be configured via software?\u003c\/strong\u003e\u003cbr\u003eYes. Baud rate, parity, and other port parameters are configurable through the Yokogawa System View configuration environment.\u003c\/p\u003e","brand":"YOKOGAWA","offers":[{"title":"Default Title","offer_id":51851076043064,"sku":"NFAI543-S50 S1","price":188.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0893\/1616\/3896\/files\/NFAI543-S00_S12.jpg?v=1770860833","url":"https:\/\/www.automodulexpert.com\/products\/yokogawa-alr121-s51-s1-centum-vp-serial-communication-module","provider":"AutoModuleXpert Ltd.","version":"1.0","type":"link"}