{"product_id":"yokogawa-alr121-s01-serial-communication-module","title":"Yokogawa ALR121-S01 Serial Communication Module","description":"\u003ch2\u003eYokogawa ALR121-S01 Serial Communication Module\u003c\/h2\u003e\n\u003cp\u003eConfigured for subsystem data exchange in CENTUM CS 3000 and CENTUM VP platforms, the \u003cstrong\u003eYokogawa ALR121-S01\u003c\/strong\u003e (base model \u003cstrong\u003eALR121\u003c\/strong\u003e) provides direct electrical interfacing between the DCS and external serial devices using RS-422\/RS-485 physical layers. The module executes deterministic half-duplex transmission without protocol translation overhead.\u003c\/p\u003e\n\u003ch3\u003eHardware Specifications\u003c\/h3\u003e\n\u003cfigure class=\"table\"\u003e\n\u003ctable\u003e\n\u003cthead\u003e\n\u003ctr\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\u003eBrand\u003c\/td\u003e\n\u003ctd\u003eYokogawa\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOrigin\u003c\/td\u003e\n\u003ctd\u003eJapan\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eWeight\u003c\/td\u003e\n\u003ctd\u003e0.34 kg\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eDimensions\u003c\/td\u003e\n\u003ctd\u003eNot specified in source data\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOperating Temp\u003c\/td\u003e\n\u003ctd\u003eStandard industrial range (conformal coated)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePower Consumption\u003c\/td\u003e\n\u003ctd\u003e0.5 A @ backplane supply\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eInterface\u003c\/td\u003e\n\u003ctd\u003eRS-422 \/ RS-485\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eNumber of Ports\u003c\/td\u003e\n\u003ctd\u003e2 (dual-port, 2-wire\/4-wire selectable)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTransmission Speed\u003c\/td\u003e\n\u003ctd\u003e1200, 2400, 4800, 9600, 19200, 38400 bps\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMax Distance\u003c\/td\u003e\n\u003ctd\u003e15 m (RS-422), 1200 m (RS-485)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSupported Protocols\u003c\/td\u003e\n\u003ctd\u003eModbus RTU \/ ASCII, custom serial protocols\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/figure\u003e\n\u003ch3\u003eChannel-to-Channel Isolation and CJ Compensation\u003c\/h3\u003e\n\u003cp\u003eThe ALR121-S01 employs channel-to-channel isolation to prevent ground loop formation across serial links in multi-node configurations. Electrical separation is maintained between each port and the backplane control bus. In installations involving analog subsystems sharing the same rack, cold junction compensation is applied at the connected I\/O level to correct thermocouple reference errors, ensuring stable temperature-referenced data transmission through the serial gateway.\u003c\/p\u003e\n\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\n\u003cp\u003eQ: Does the ALR121-S01 support hot-swapping?\u003c\/p\u003e\n\u003cp\u003eA: Hot-swap replacement is supported only when installed in a redundant pair; single-module operation requires system shutdown before removal.\u003c\/p\u003e\n\u003cp\u003eQ: What is the lag time after data transmission?\u003c\/p\u003e\n\u003cp\u003eA: The module introduces a fixed 1 ms lag after completing each transmission frame.\u003c\/p\u003e\n\u003cp\u003eQ: Can RS-422 and RS-485 be used simultaneously?\u003c\/p\u003e\n\u003cp\u003eA: No. Each port must be configured identically; mixed physical layer operation on a single module is not supported.\u003c\/p\u003e\n\u003ch3\u003eField Installation Guidelines\u003c\/h3\u003e\n\u003cp\u003eInstall the ALR121-S01 in designated Yokogawa mounting bases with verified backplane engagement. Use shielded twisted-pair cable for all serial runs; terminate shields at the DCS cabinet earth busbar only. For RS-485 multipoint networks, maintain consistent biasing resistors across all nodes to prevent signal reflection. Verify screw terminal torque to 0.5 N·m during commissioning to avoid intermittent contact on clamp terminals. Ensure conformal-coated surfaces remain free from solvent exposure during handling.\u003c\/p\u003e","brand":"Yokogawa","offers":[{"title":"Default Title","offer_id":44209089151064,"sku":"ALR121-S01","price":100.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0670\/2039\/0488\/files\/ALR121-S01-3.jpg?v=1780976366","url":"https:\/\/www.industriaxplc.com\/products\/yokogawa-alr121-s01-serial-communication-module","provider":"IndustriaX Limited","version":"1.0","type":"link"}