This is an industrial grade online nitrate ion sensor that uses PVC membrane ion selective electrode method to detect nitrate concentration in water in real time. The default range is 0~100 mg/L (optional 0~1000 mg/L), with an accuracy of ± 5% or ± 2 mg/L, and a response time of less than 60 seconds. Built in Pt1000 automatic temperature compensation, supports RS-485 (Modbus RTU) output and optional 4-20mA, making it easy to connect to PLC, DCS and other systems. 3/4 NPT thread installation, IP68 protection, optional POM+316L corrosion-resistant material for housing, suitable for sewage treatment, surface water monitoring, pipeline and tank immersion measurement.