{"product_id":"communication-module-yokogawa-alr121-s51-s1-rs-422-rs-485","title":"Communication Module | Yokogawa ALR121-S51 S1 RS-422\/RS-485","description":"\u003ch2\u003eYokogawa ALR121-S51 Serial Communication Module\u003c\/h2\u003e\n\u003cp\u003eThe \u003cstrong\u003eYokogawa ALR121-S51 S1\u003c\/strong\u003e, also cataloged as the \u003cstrong\u003eALR121\u003c\/strong\u003e Serial Communication Module, operates as a dedicated hardware component for half-duplex serial subsystem interfacing within CENTUM VP and CS 3000 Field Control Station networks.\u003c\/p\u003e\n\u003ch3\u003eSuffix Breakdown \u0026amp; Model Matrix\u003c\/h3\u003e\n\u003cfigure class=\"table\"\u003e\n\u003ctable\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth\u003e\u003cstrong\u003eModel \/ Suffix Code\u003c\/strong\u003e\u003c\/th\u003e\n\u003cth\u003e\u003cstrong\u003eSpecification\u003c\/strong\u003e\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eALR121\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eSerial Communication Module (2-channel, RS-422\/RS-485)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003e-S\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eStandard type module\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003e5\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eStandard status display with single slot mounting execution\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003e1\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eBasic option code configuration\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eS1\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eStyle code 1 hardware revision\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/figure\u003e\n\u003ch3\u003eHardware Specifications\u003c\/h3\u003e\n\u003cfigure class=\"table\"\u003e\n\u003ctable\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth\u003e\u003cstrong\u003eParameter\u003c\/strong\u003e\u003c\/th\u003e\n\u003cth\u003e\u003cstrong\u003eSpecification\u003c\/strong\u003e\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\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\u003e100 mm x 80 mm x 30 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOperating Temp\u003c\/td\u003e\n\u003ctd\u003e-40 to +75 deg C\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePower Consumption\u003c\/td\u003e\n\u003ctd\u003e0.5 A at 24 VDC\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eInterface Ports\u003c\/td\u003e\n\u003ctd\u003e2 ports (RS-422\/RS-485 4-wire system)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCommunication Mode\u003c\/td\u003e\n\u003ctd\u003eHalf-duplex, Start-stop synchronization\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\u003eTransmission Distance\u003c\/td\u003e\n\u003ctd\u003eUp to 1200 m (RS-485), 15 m (RS-422)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eIsolation Voltage\u003c\/td\u003e\n\u003ctd\u003e2000 VAC for 1 min\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMounting Compatibility\u003c\/td\u003e\n\u003ctd\u003eAFV30, AFV40, ANB10, ANB11 nodes\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/figure\u003e\n\u003ch3\u003e4-20 mA HART Loop Protocol \u0026amp; Channel Isolation\u003c\/h3\u003e\n\u003cp\u003eThe Yokogawa ALR121-S51 S1 serial communication module provides optical channel-to-channel isolation rated at 2000 VAC for 1 minute between field side wiring and the station backplane. This galvanic isolation suppresses common-mode noise and ground potential differences when bridging Modbus RTU devices, FA-M3 PLCs, or 4-20 mA HART multi-drop loop gateways to the Field Control Station (FCS). Differential signal transmission via 4-wire RS-422 and RS-485 networks prevents data corruption across high-density I\/O racks.\u003c\/p\u003e\n\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\n\u003cp\u003eQ: Can the ALR121-S51 module be inserted into an active Field Control Station backplane slot during live operation?\u003c\/p\u003e\n\u003cp\u003eA: Yes, the module supports hot-swapping within compatible backplane slots (such as ANB10 or ANB11), provided system software node configuration procedures are strictly observed.\u003c\/p\u003e\n\u003cp\u003eQ: What transmission protocol codes are supported across the two independent serial ports?\u003c\/p\u003e\n\u003cp\u003eA: The module supports both ASCII and Binary transmission codes with configurable 7 or 8 bit data character lengths, odd\/even\/no parity, and 1 or 2 stop bits.\u003c\/p\u003e\n\u003cp\u003eQ: Is termination resistance required for RS-485 multipoint bus topology setups?\u003c\/p\u003e\n\u003cp\u003eA: Yes, terminal resistors must be engaged at both physical ends of the RS-485 bus network line to match the 100-ohm line impedance and eliminate signal reflections.\u003c\/p\u003e\n\u003ch3\u003eField Installation Guidelines\u003c\/h3\u003e\n\u003cp\u003eEngineers must follow established installation guidelines when wiring serial subsystem interfaces:\u003c\/p\u003e\n\u003col\u003e\n\u003cli\u003eInsert the module into an open I\/O slot of an AFV30, AFV40, ANB10, or ANB11 base unit and tighten the module securing screws.\u003c\/li\u003e\n\u003cli\u003eRoute shielded twisted-pair cables (such as AKB131 through AKB134) separately from high-voltage AC cables to reduce inductive noise coupling.\u003c\/li\u003e\n\u003cli\u003eConnect cable shield drain wires directly to the system protective earth (PE) ground terminal at a single point.\u003c\/li\u003e\n\u003cli\u003eVerify baud rate, parity bits, and station address parameters in software to match connected Modbus or subsystem hardware before putting the link online.\u003c\/li\u003e\n\u003c\/ol\u003e","brand":"Yokogawa","offers":[{"title":"Default Title","offer_id":43901482827866,"sku":"ALR121-S51 S1","price":99.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0710\/5957\/0778\/files\/641._dfcacb94-0b0d-49bc-9bbe-c1c454d085fd.jpg?v=1787624043","url":"https:\/\/www.spareoil.com\/products\/communication-module-yokogawa-alr121-s51-s1-rs-422-rs-485","provider":"SpareOil Automation","version":"1.0","type":"link"}