ST-500W Inline PTSA Sensor for Industry Standard Tee Assemblies

The ST-500 Fit for Existing Industry Known Tee Assemblies!

Measures for PTSA at an expanded range (0–300ppb), while simultaneously compensating for Color & Turbidity Interference, to provide a more accurate dosage reading. This variant fits perfectly into WALCHEM® and other industry-known tee assemblies! Use the MA-WB Bluetooth® Adapter to enable wireless monitoring, calibration & cleanliness diagnostics via the uPyxis® app!

CE Mark 



The ST-500W is a stainless steel inline PTSA Pyxis smart sensor. It is uniquely designed to be directly inserted into the WALCHEM® and alternative fluorometer tee assemblies. The ST-500W is designed for the WALCHEM® tee system. Most fluorometers have similar dimensions to this system.  This allows drop-in installation into both designs of inline tee assemblies without the need for plumbing modifications.

The ST-500W is identical in internal design and function to the ST-500 Series inline PTSA sensor platform. This offers the industry a proprietary design for the direct measurement of PTSA utilizing LED UV light sources. As well as being specifically designed for use in industrial cooling water and process water treatment applications.

The ST-500W offers the Pyxis proprietary algorithms to determine the concentrations of PTSA while measuring sample turbidity and color in highly contaminated waters. The ST-500W offers a combination of 4-20mA as well as RS-485 Modbus output signals in 8-Pin cable format. As well as being Bluetooth Enabled for wireless cleanliness diagnostics and calibration. When used with MA-CR or PowerPACK Series Bluetooth Adapters and the uPyxis APP for Mobile or Desktop devices. The ST-500W comes equipped with 1.5m (4.9ft) bulk-head cable with quick adapter as well as 1.5m (4.9ft) flying lead cable with quick adapter, enabling rapid wiring to any microprocessor controller, PLC or DCS system.


Item ST-500W Inline PTSA Sensor
Part Number 58802
PTSA Output Scale 0-200ppb
PTSA Max Range via uPyxis® 0-300ppb
PTSA Precision/Accuracy ±1ppb
Excitation/Emission LED 365/410nm
Power Supply 22-26VDC, Power Consumption – 1W
Outputs Isolated 4-20mA Analog & Isolated RS-485 Digital – 7-Pin
Installation ST-001 Inline Tee (PROVIDED), 3/4inch FNPT
Weight 500g (1.1lbs)
Operation Pressure 100psi (6.9Bar)
Operation Temperature 4-49 °C (40-120 °F)
Storage Temperature -20-60 °C (-4–140 °F)
Material 304 Stainless Steel
Rating IP67, Dustproof & Waterproof
Regulation CE + RoHS
Dimensions 6.8in (172.7mm) L x 1.44in (36.6mm) D
Cable Length 5ft, Terminated with IP67 Adapter + 1.5ft Flying Lead

Support Documents

ST-500W User Manual V1.1

ST-500W Data Sheet



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