{"product_id":"yokogawa-alr121-s00-s1-serial-modbus-communication-module","title":"YOKOGAWA ALR121-S00 S1 Serial Modbus Communication Module","description":"\u003ch2\u003eYOKOGAWA ALR121-S00 S1 Serial Communication Module\u003c\/h2\u003e\n\u003cp\u003eConfigured for serial data exchange in CENTUM VP, CS 3000, and Safety Control Station (SCS) platforms, the \u003cstrong\u003eYOKOGAWA ALR121-S00 S1\u003c\/strong\u003e (\u003cstrong\u003eALR121-S00\u003c\/strong\u003e Serial Communication Module) provides direct physical\/electrical execution. The hardware provides RS-422 and RS-485 interfaces to execute Modbus communication protocols, bridging internal controller data directly to external supervisory master systems.\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\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-S00 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\u003eUSA\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eWeight\u003c\/td\u003e\n\u003ctd\u003e1.5 kg\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eDimensions\u003c\/td\u003e\n\u003ctd\u003e2.2 cm x 12.4 cm x 12.6 cm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOperating Temp\u003c\/td\u003e\n\u003ctd\u003e0 to 55 deg C\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePower Consumption\u003c\/td\u003e\n\u003ctd\u003e24 VDC nominal backplane supply\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eInterface Ports\u003c\/td\u003e\n\u003ctd\u003eRS-422 \/ RS-485 serial interfaces (4-wire system)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBus Protocol\u003c\/td\u003e\n\u003ctd\u003eModbus RTU \/ ASCII communication protocol\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eConnection Topology\u003c\/td\u003e\n\u003ctd\u003ePoint-to-point (RS-422), Multipoint (RS-485)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eIsolation Rating\u003c\/td\u003e\n\u003ctd\u003eGalvanic isolation between serial channels and system backplane bus\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/figure\u003e\n\u003ch3\u003eSerial Protocol Execution and Channel Isolation\u003c\/h3\u003e\n\u003cp\u003eThe module manages serial transmission across dedicated RS-422 point-to-point links and RS-485 multi-drop networks, utilizing standard 4-wire hardware connections. Integrated galvanic isolation shields internal backplane processing logic from voltage spikes, ground loops, and electrical noise present along external serial field wiring. The onboard controller manages Modbus register access to read and write variables inside host control stations, maintaining channel diagnostic LED states to indicate active data transmission, port configuration faults, and frame errors in real time.\u003c\/p\u003e\n\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\n\u003cp\u003eQ: How does the serial interface handle channel-to-system electrical noise isolation?\u003c\/p\u003e\n\u003cp\u003eA: Integrated galvanic isolation barriers completely decouple the RS-422\/RS-485 transceiver circuitry from the internal controller backplane, preventing field loop voltage transients from affecting CPU bus operation.\u003c\/p\u003e\n\u003cp\u003eQ: What topology configuration options exist for the serial ports?\u003c\/p\u003e\n\u003cp\u003eA: The hardware supports 4-wire RS-422 point-to-point configurations for dedicated single-device links, as well as 4-wire RS-485 multipoint bus networks connecting multiple Modbus slaves.\u003c\/p\u003e\n\u003cp\u003eQ: Does the module support Modbus data modification from external systems without stopping controller execution?\u003c\/p\u003e\n\u003cp\u003eA: Yes, external Modbus master devices read and modify designated data registers within the controller system asynchronously over the serial link while host control logic runs continuously.\u003c\/p\u003e\n\u003ch3\u003eField Installation Guidelines\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eDisconnect backplane rack power before seating or removing the communication module from the system chassis slot.\u003c\/li\u003e\n\u003cli\u003eUse shielded twisted-pair cabling designed specifically for RS-422\/RS-485 industrial communication networks to minimize signal attenuation.\u003c\/li\u003e\n\u003cli\u003eConnect cable shield drain wires directly to the system cabinet earth ground bar, ensuring the field terminal end remains isolated to prevent ground loops.\u003c\/li\u003e\n\u003cli\u003eInstall termination resistors across the receiver terminals at the physical ends of the RS-485 multipoint network to suppress line reflections.\u003c\/li\u003e\n\u003cli\u003eMaintain clear airflow around chassis card slots so operating temperatures remain strictly within the 0 to 55 deg C environmental limits.\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Yokogawa","offers":[{"title":"Default Title","offer_id":43914042572890,"sku":"ALR121","price":99.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0710\/5957\/0778\/files\/92_107164f4-defe-4f31-92de-d2d8b82aea08.jpg?v=1787729110","url":"https:\/\/www.spareoil.com\/products\/yokogawa-alr121-s00-s1-serial-modbus-communication-module","provider":"SpareOil Automation","version":"1.0","type":"link"}