The ST-500W is a stainless steel inline PTSA sensor designed to drop directly into WALCHEM® and other industry-standard fluorometer tee assemblies, without needing plumbing modifications. It is internally identical to the standard ST-500 Series in design and function, using LED UV light sources for direct PTSA measurement.

The ST-500W applies Pyxis’s proprietary compensation algorithms to hold PTSA accuracy even where sample turbidity or colour would otherwise distort a standard fluorometer reading, making it suited to industrial cooling water and process water treatment applications with variable water quality.

Output is via 4-20mA analog and RS-485 Modbus in 8-pin cable format, with Bluetooth enabled for wireless cleanliness diagnostics and calibration via the MA-CR adapter and uPyxis app. The unit ships with a 1.5m bulkhead cable and a 1.5m flying lead cable for rapid wiring to a PLC, DCS, or third-party controller.

Key specifications:

• PTSA output scale: 0-200ppb, max range via uPyxis app: 0-300ppb
• Accuracy: ±1ppb
• Excitation/Emission: LED 365/410nm
• Outputs: isolated 4-20mA analog and isolated RS-485 digital, 7-pin
• Installation: ST-001 inline tee (provided), 3/4″ FNPT, fits WALCHEM-style tees
• Material: 304 stainless steel, IP67
• Operating temperature: 4-49°C
• Power: 22-26VDC, 1W