{"product_id":"yokogawa-flxa21-ph-orp-conductivity-dissolved-oxygen-controller","title":"Yokogawa FLXA21 pH ORP Conductivity Dissolved Oxygen Controller","description":"\u003ch2\u003eYokogawa FLXA21 Modular 2-Wire Liquid Analyzer\u003c\/h2\u003e\n\u003cp\u003eThe \u003cstrong\u003eYokogawa FLXA21-D-P-D-AB-C1-NN-A-N-LA-N-NN\/UM\/CD4\u003c\/strong\u003e, also cataloged as the \u003cstrong\u003eFLXA21\u003c\/strong\u003e Liquid Analyzer Controller, operates as a dedicated hardware component for continuous online liquid property measurement within OpreX Analyzers platforms and CENTUM VP DCS integrated architectures. Operating on a 2-wire 24 VDC loop-powered circuit, the analyzer processes field signals for pH\/ORP, contacting conductivity, inductive conductivity, and dissolved oxygen parameters. The unit executes direct dual-sensor signal processing and converts sensor inputs into an isolated 4-20 mA DC analog output superimposed with digital HART, FOUNDATION Fieldbus, or PROFIBUS PA communication protocols.\u003c\/p\u003e\n\u003ch3\u003eHardware Specifications\u003c\/h3\u003e\n\u003cfigure class=\"table\"\u003e\n\u003ctable style=\"width: 100%; height: 470.25px;\"\u003e\n\u003cthead\u003e\n\u003ctr style=\"height: 19.5938px;\"\u003e\n\u003cth style=\"width: 28.3382%; height: 19.5938px;\"\u003e\u003cstrong\u003eParameter\u003c\/strong\u003e\u003c\/th\u003e\n\u003cth style=\"width: 67.205%; height: 19.5938px;\"\u003e\u003cstrong\u003eSpecification\u003c\/strong\u003e\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr style=\"height: 39.1875px;\"\u003e\n\u003ctd style=\"width: 28.3382%; height: 39.1875px;\"\u003eModel\u003c\/td\u003e\n\u003ctd style=\"width: 67.205%; height: 39.1875px;\"\u003eFLXA21-D-P-D-AB-C1-NN-A-N-LA-N-NN\/UM\/CD4\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"height: 19.5938px;\"\u003e\n\u003ctd style=\"width: 28.3382%; height: 19.5938px;\"\u003eBrand\u003c\/td\u003e\n\u003ctd style=\"width: 67.205%; height: 19.5938px;\"\u003eYokogawa\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"height: 19.5938px;\"\u003e\n\u003ctd style=\"width: 28.3382%; height: 19.5938px;\"\u003eOrigin\u003c\/td\u003e\n\u003ctd style=\"width: 67.205%; height: 19.5938px;\"\u003eJapan\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"height: 39.1875px;\"\u003e\n\u003ctd style=\"width: 28.3382%; height: 39.1875px;\"\u003eWeight\u003c\/td\u003e\n\u003ctd style=\"width: 67.205%; height: 39.1875px;\"\u003e1 kg (Plastic housing) \/ 2 kg (Stainless steel)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"height: 39.1875px;\"\u003e\n\u003ctd style=\"width: 28.3382%; height: 39.1875px;\"\u003eDimensions\u003c\/td\u003e\n\u003ctd style=\"width: 67.205%; height: 39.1875px;\"\u003e144 x 144 x 151 mm (Plastic) \/ 165 x 165 x 160 mm (Stainless)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"height: 19.5938px;\"\u003e\n\u003ctd style=\"width: 28.3382%; height: 19.5938px;\"\u003eOperating Temp\u003c\/td\u003e\n\u003ctd style=\"width: 67.205%; height: 19.5938px;\"\u003e-20 to +55 deg C\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"height: 39.1875px;\"\u003e\n\u003ctd style=\"width: 28.3382%; height: 39.1875px;\"\u003ePower Consumption\u003c\/td\u003e\n\u003ctd style=\"width: 67.205%; height: 39.1875px;\"\u003e24 VDC loop powered (Operating voltage 17 to 40 VDC)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"height: 19.5938px;\"\u003e\n\u003ctd style=\"width: 28.3382%; height: 19.5938px;\"\u003eOutput Signal\u003c\/td\u003e\n\u003ctd style=\"width: 67.205%; height: 19.5938px;\"\u003eIsolated 4-20 mA DC, 2-wire system\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"height: 39.1875px;\"\u003e\n\u003ctd style=\"width: 28.3382%; height: 39.1875px;\"\u003eDigital Protocol\u003c\/td\u003e\n\u003ctd style=\"width: 67.205%; height: 39.1875px;\"\u003eHART, FOUNDATION Fieldbus, or PROFIBUS PA\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"height: 39.1875px;\"\u003e\n\u003ctd style=\"width: 28.3382%; height: 39.1875px;\"\u003eDisplay\u003c\/td\u003e\n\u003ctd style=\"width: 67.205%; height: 39.1875px;\"\u003eBlack\/white LCD touch screen (213 x 160 pixels)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"height: 39.1875px;\"\u003e\n\u003ctd style=\"width: 28.3382%; height: 39.1875px;\"\u003eIngress Protection\u003c\/td\u003e\n\u003ctd style=\"width: 67.205%; height: 39.1875px;\"\u003eIP66 \/ NEMA 4X rated\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"height: 39.1875px;\"\u003e\n\u003ctd style=\"width: 28.3382%; height: 39.1875px;\"\u003eSensor Inputs\u003c\/td\u003e\n\u003ctd style=\"width: 67.205%; height: 39.1875px;\"\u003eUp to 2 sensors of the same measurement type\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"height: 58.7812px;\"\u003e\n\u003ctd style=\"width: 28.3382%; height: 58.7812px;\"\u003eMeasurement Types\u003c\/td\u003e\n\u003ctd style=\"width: 67.205%; height: 58.7812px;\"\u003epH\/ORP, contacting conductivity, inductive conductivity, dissolved oxygen\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/figure\u003e\n\u003ch3\u003eProcess Control \u0026amp; DCS Instrumentation Characteristics\u003c\/h3\u003e\n\u003cp\u003eConfigured for field deployment, the analyzer executes continuous sensor diagnostics including glass electrode impedance monitoring, polarization detection, and sensor slope calculations to predict maintenance intervals. The 4-20 mA HART loop protocol passes primary variable data along with secondary diagnostic flags directly to host controller systems. Channel-to-channel isolation prevents ground loop current interference when connecting two liquid sensors to a single transmitter chassis, maintaining signal integrity across long cable distances.\u003c\/p\u003e\n\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\n\u003cp\u003eQ: How does the dual-sensor capability operate on the FLXA21 analyzer platform?\u003c\/p\u003e\n\u003cp\u003eA: The analyzer accepts up to two physical sensors of the same measurement type (such as two pH electrodes or two conductivity cells). The internal signal processor continuously reads both channels, enabling dual-point monitoring, redundant sensor failover, or average value output calculation to the host control system.\u003c\/p\u003e\n\u003cp\u003eQ: What line power requirements and wiring constraints apply to this 2-wire analyzer?\u003c\/p\u003e\n\u003cp\u003eA: The analyzer derives operational power directly from the 24 VDC signal loop. The DC supply voltage must remain between 17 VDC and 40 VDC at the analyzer terminals, accounting for loop resistance across the 4-20 mA current wire run.\u003c\/p\u003e\n\u003cp\u003eQ: How does the unit maintain measurement accuracy under harsh process conditions?\u003c\/p\u003e\n\u003cp\u003eA: The housing features an IP66 and NEMA 4X ingress protection rating to resist moisture and corrosive vapors. Furthermore, internal software algorithms apply continuous temperature compensation via Pt1000 or NTC thermistor inputs to correct raw liquid measurement signals in real time.\u003c\/p\u003e\n\u003ch3\u003eField Installation Guidelines\u003c\/h3\u003e\n\u003col\u003e\n\u003cli\u003eMount the FLXA21 housing securely to a 2-inch vertical\/horizontal pipe, wall surface, or panel cutout using the supplied UM mounting hardware kit.\u003c\/li\u003e\n\u003cli\u003eRoute signal and sensor cables through the bottom cable glands, maintaining a drip loop to prevent moisture ingress into the wiring enclosure.\u003c\/li\u003e\n\u003cli\u003eTerminate the 2-wire 24 VDC loop cable to the main power\/output terminals, ensuring proper polarity and connecting the cable shield to the internal chassis ground lug.\u003c\/li\u003e\n\u003cli\u003eWire sensor coaxial cables directly to the dedicated sensor interface terminal block, ensuring high-impedance pH signal lines remain clean and dry.\u003c\/li\u003e\n\u003cli\u003eTorque the enclosure cover screws evenly to maintain the IP66 \/ NEMA 4X weatherproof seal, and calibrate the attached sensors using the front panel touch-screen interface prior to online operation.\u003c\/li\u003e\n\u003c\/ol\u003e","brand":"Yokogawa","offers":[{"title":"Default Title","offer_id":43846477906010,"sku":"FLXA21","price":99.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0710\/5957\/0778\/files\/32._f3eaa1db-66df-4184-be63-2201d2c2e8be.jpg?v=1786695494","url":"https:\/\/www.spareoil.com\/products\/yokogawa-flxa21-ph-orp-conductivity-dissolved-oxygen-controller","provider":"SpareOil Automation","version":"1.0","type":"link"}