## I. Measurement Function 1. **Multi-parameter**: The Yokogawa FLXA21's modular design allows for measuring pH/ORP, contact & inductive conductivity, and dissolved oxygen via different sensor modules, catering to diverse needs. In chemical processes, it helps understand reaction environments better. 2. **Wide Range**: Its dissolved oxygen sensors cover ppb to ppm. pH spans -2 to 16pH, suitable for various acid-base solutions. ORP is -1500 to 1500mV, rH 0 to 100rH, temperature -30 to 140°C, conductivity 0.000μS/cm to 2000mS/cm, and resistivity 0.0Ω·cm to 1000MΩ·cm, fitting many applications. 3. **High Precision**: It shows remarkable precision. pH has ±0.01pH in linearity, repeatability and accuracy; ORP ±1mV; temperature ±0.3 - ±0.4°C; conductivity and resistivity up to ±0.5%F.S., crucial in quality-sensitive industries. ## II. Hardware Design 1. **Dual Sensor**:[Yokogawa FLXA21](https://www.cwlyautomation.com/product/4532.html "Yokogawa FLXA21") Can connect one or two same-model sensors for single or dual sensing, cutting costs and space, and ensuring continuous measurement through redundancy, vital for uninterrupted processes. 2. **Enclosure Options**: Available in plastic, stainless steel, and corrosion-resistant coated stainless steel, adaptable to different environments, like plastic for indoor use and metal ones for corrosive settings. 3. **User-friendly**: With a 213 x 160-pixel black-and-white LCD touchscreen, intuitive HMI menu and 12-language support, Yokogawa FLXA21's easy to operate, facilitating global use. ## III. Communication and Output 1. **Output**: Features a 4 - 20mA DC output and supports two-way HART digital communication, making Yokogawa FLXA21 easy to integrate with [PLC](http://www.cwgreentech.com/product/4.html "PLC")s, with analog and digital data transfer capabilities. 2. **Protocols**: Besides HART, offers FF and PF communication options, enhancing its versatility to fit different industrial networks. ## IV. Other Features 1. **Self-diagnosis**: Monitors sensor parameters in real-time to detect electrode contamination, reducing maintenance costs by enabling timely fixes. 2. **Maintenance Estimation**: Stores recent five calibration results to predict maintenance and calibration times, minimizing downtime. 3. **Temperature Compensate**: Has both auto and manual temperature compensation based on relevant equations or coefficients, ensuring accurate results in varying temperature conditions. ## V. Application Areas 1. **Chemical**: Widely used in the chemical industry to monitor solution concentrations and reaction parameters for safe production, like in fertilizer making. 2. **Pharmaceutical**: Measures water conductivity etc. to meet strict GMP requirements for drug quality and safety. 3. **Food & Beverage**: [Yokogawa FLXA21](https://www.cwlyautomation.com/product/4532.html "Yokogawa FLXA21") Used for water quality, juice concentration and beer fermentation dissolved oxygen monitoring to ensure product quality and taste. 4. **Environmental**: Monitors sewage parameters in real-time to optimize treatment and ensure compliance with discharge standards, protecting the environment.