{"product_id":"yokogawa-alr121-s51-rs-422-rs-485-communication-card","title":"Yokogawa ALR121-S51 RS-422 RS-485 Communication Card","description":"\u003cdiv class=\"product-description-container\"\u003e\n\u003ch3\u003eProduct Overview\u003c\/h3\u003e\n\u003cp\u003eGlobal PLC Spare HUB Review\u003c\/p\u003e\n\u003cp\u003eIndustrial automation environments demand robust data exchange across distributed control nodes. Engineers deploy the \u003cstrong\u003e\u003cspan style=\"color: #0056b3;\"\u003eALR121-S51\u003c\/span\u003e\u003c\/strong\u003e serial communication module to bridge legacy controllers with modern serial field devices. This dual-port hardware card manages half-duplex communication protocols smoothly across extended plant floors. Operators rely on its deterministic start-stop synchronization to prevent packet collision in harsh manufacturing environments. Global PLC Spare HUB's Insight notes that proper serial termination prevents high-frequency signal reflections on long cable runs.\u003c\/p\u003e\n\u003ch3\u003eTechnical Specifications\u003c\/h3\u003e\n\u003cp\u003eGlobal PLC Spare HUB's Insight\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eBrand:\u003c\/strong\u003e Yokogawa\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eModel Number:\u003c\/strong\u003e \u003cstrong\u003e\u003cspan style=\"color: #0056b3;\"\u003eALR121-S51\u003c\/span\u003e\u003c\/strong\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSeries:\u003c\/strong\u003e \u003cstrong\u003e\u003cspan style=\"color: #0056b3;\"\u003eALR121\u003c\/span\u003e\u003c\/strong\u003e Serial Communication Module\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eInterface Type:\u003c\/strong\u003e RS-422 \/ RS-485 (4-wire system)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eConnection Topology:\u003c\/strong\u003e Point-to-point for RS-422, Multipoint for RS-485\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTransmission Speed:\u003c\/strong\u003e 1200, 2400, 4800, 9600, 19200, or 38400 bps\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCommunication Function:\u003c\/strong\u003e Half-duplex\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSynchronization Method:\u003c\/strong\u003e Start-stop synchronization\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTransmission Code:\u003c\/strong\u003e ASCII or Binary\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCharacter Length:\u003c\/strong\u003e 7 or 8 bits\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eStop Bit Length:\u003c\/strong\u003e 1 or 2 bits\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eParity Check Mode:\u003c\/strong\u003e None, Even, or Odd\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLag Time After Data Transmission:\u003c\/strong\u003e 1 ms wait time before receiving data\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMaximum Transmission Distance:\u003c\/strong\u003e 1200 meters total extended length\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSignal Frequency Response:\u003c\/strong\u003e Baseband serial pulse train up to 38.4 kbps\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLinearity and Resolution:\u003c\/strong\u003e Digital bit-stream translation with zero analog conversion error\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCurrent Consumption:\u003c\/strong\u003e 0.5 A\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eModule Weight:\u003c\/strong\u003e 0.34 kg\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eInstallation Guide\u003c\/h3\u003e\n\u003cp\u003eGlobal PLC Spare HUB Review\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eMount the \u003cstrong\u003e\u003cspan style=\"color: #0056b3;\"\u003eALR121-S51\u003c\/span\u003e\u003c\/strong\u003e directly onto compatible base plates like ANB10☐, ANB11☐, ANR10☐, AFF50☐, AFV10☐, AFV30☐, or AFV40☐.\u003c\/li\u003e\n\u003cli\u003eVerify rack power isolation before inserting the circuit board into the designated slot.\u003c\/li\u003e\n\u003cli\u003eSecure field wires using 3-pair shielded cables such as AKB161 or AKB162.\u003c\/li\u003e\n\u003cli\u003eFasten stripped wire ends securely to the terminal block using M4 screws across the 5-pole dual rows.\u003c\/li\u003e\n\u003cli\u003eGround the cable shield properly at one end to minimize electromagnetic induction from nearby power inverters.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eCompatibility and Environmental Tolerance\u003c\/h3\u003e\n\u003cp\u003eGlobal PLC Spare HUB's Insight\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eSystem Compatibility:\u003c\/strong\u003e Integrates seamlessly into Centum CS 3000 and Centum VP distributed control architectures.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eEnvironmental Tolerance:\u003c\/strong\u003e Built with standard G3 ISA conformal coating to withstand corrosive gases in chemical plants.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOperating Temperature Range:\u003c\/strong\u003e Designed for standard industrial control room thresholds.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eInterference Resistance:\u003c\/strong\u003e Built-in optical isolation protects internal system buses from external voltage surges.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eMaintenance, Diagnostics, and Operational Experience\u003c\/h3\u003e\n\u003cp\u003eGlobal PLC Spare HUB Review\u003c\/p\u003e\n\u003cp\u003eTechnicians monitor onboard LED indicators to verify active transmit and receive data traffic instantly. Field engineers note that intermittent CRC framing errors usually stem from missing terminating resistors on long RS-485 multi-drop lines. Clean terminal blocks periodically to prevent oxidation dropouts in high-humidity facilities.\u003c\/p\u003e\n\u003ch3\u003eCertifications, Shipping, and Warranty\u003c\/h3\u003e\n\u003cp\u003eGlobal PLC Spare HUB's Insight\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eCertification Standards:\u003c\/strong\u003e Complies with ISA Standard G3 harsh environment specifications.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eShipping Logistics:\u003c\/strong\u003e Dispatched within 24 to 48 hours using reliable carriers including FedEx, UPS, and DHL.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWarranty Terms:\u003c\/strong\u003e Backed by a comprehensive 12-month operational warranty.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePackage Contents:\u003c\/strong\u003e One \u003cstrong\u003e\u003cspan style=\"color: #0056b3;\"\u003eALR121-S51\u003c\/span\u003e\u003c\/strong\u003e communication module and factory compliance documentation.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eTypical Application Scenarios\u003c\/h3\u003e\n\u003cp\u003eGlobal PLC Spare HUB Review\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eConnecting multi-vendor variable frequency drives to a central CENTUM controller.\u003c\/li\u003e\n\u003cli\u003eIntegrating legacy barcode scanners and weighing scales into automated batching systems.\u003c\/li\u003e\n\u003cli\u003eManaging SCADA telemetry data across remote terminal units in water treatment plants.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\n\u003cp\u003eGlobal PLC Spare HUB Review\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCan I connect an RS-422 device directly to an RS-485 multi-drop network using this card?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eNo, the physical layer wiring topology differs between point-to-point RS-422 and multipoint RS-485 architectures.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat causes frame framing errors on the \u003cstrong\u003e\u003cspan style=\"color: #0056b3;\"\u003eALR121-S51\u003c\/span\u003e\u003c\/strong\u003e serial port?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eBaud rate mismatches or electromagnetic interference on unshielded cable runs typically trigger data framing errors.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow do I select the correct transmission speed for my field instrument?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eMatch the baud rate setting of the connected peripheral device exactly within the system engineering software configuration.\u003c\/p\u003e\n\u003ch3\u003eSelection Guide\u003c\/h3\u003e\n\u003cp\u003eGlobal PLC Spare HUB's Insight\u003c\/p\u003e\n\u003cp\u003eVerify your controller rack model before ordering to ensure physical slot alignment matches the \u003cstrong\u003e\u003cspan style=\"color: #0056b3;\"\u003eALR121-S51\u003c\/span\u003e\u003c\/strong\u003e specification. Choose standard G3 coated variants when deploying hardware in pulp mills, refineries, or coastal wastewater facilities. Match your cable shielding requirements to plant layout distances to maintain signal integrity.\u003c\/p\u003e\n\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0722\/7863\/8774\/files\/ALR121.png?v=1785133556\" alt=\"\"\u003e\u003c\/p\u003e\n\u003c\/div\u003e","brand":"Yokogawa","offers":[{"title":"Default Title","offer_id":45013913534646,"sku":"ALR121-S51","price":30.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0722\/7863\/8774\/files\/ALR121-S51_daeeac8e-9cc8-42df-bdea-977c9b29213c.jpg?v=1785132445","url":"https:\/\/www.plcsparehub.com\/products\/yokogawa-alr121-s51-rs-422-rs-485-communication-card","provider":"Global PLC Spare Hub","version":"1.0","type":"link"}