UVAS plus sc Sensor

Hach’s UVAS plus sc digital UV probe is designed for the reagent-free determination of the organic load via the spectral absorption coefficient (SAC) in the medium or in the bypass. Reliable measurement values are immediately available due to the direct UV measurement. The low maintenance sensor is self-cleaning and with its stainless steel housing even applicable in difficult environmental conditions.

The UVAS plus sc probe covers a broad spectrum of applications, including: protection of treatment plants from industrial dischargers, monitoring shock loads from internal plant processes, control of activated sludge processes, control methanol feed in BNR based on organic loading, final effluent monitoring and monitoring efficiency of UV disinfection processes.

The sensor can be connected to all SC controllers thus providing versatile output options including 4-20 mA Output, Modbus RS485, Profibus, or HART.

This instrument connects to Claros, Hach’s innovative Water Intelligence System, enabling you to seamlessly connect and manage instruments, data, and process – anywhere, anytime. The result is greater confidence in your data and improved efficiency in your operations. To unlock the full potential of Claros, insist on Claros Enabled instruments.


Continuous, Automatic Early Warning Systems

Use the Hach UVAS plus sc UV Absorbance/Transmittance Sensor to continuously protect plant treatment processes from high influent organic loads. Operators can use the continuous readings of UV absorbance or transmission to watch for sudden changes in organic load that would require alternate treatment procedures.

Control Activated Sludge Processes

Activated sludge processes require precise balancing of organic load, aeration, and nutrients. Continuous trending of the organics in the system with the UVAS plus sc sensor can help operators know how to balance other factors resulting in cost and time savings.

Self-cleaning Wiper System

With the UVAS plus sc sensor submerged in the sample stream, the detector windows are automatically cleaned by a built-in wiper that eliminates surface films or particles that can diminish accuracy.

Monitor Efficiency of UV Disinfection Process

UV light transmittance (UVT) is critical in the delivery of dose in a UV reactor. The delivered dose is determined by, among other things, the UVT of the source water, the intensity of the UV lamps, and the flow rate of the water source. UVT can be affected by many factors, from a simple change in the seasons to storm events. Potential changes in UVT should be considered in a UV disinfection system for optimized dose delivery. Hach’s UVAS plus sc is designed to provide continuous UVT measurement of pre-disinfected source water. Operational costs related to sampling for UVT may be reduced with continuous online measurement. Data can immediately be incorporated into the operation in real time.

Self Diagnostics and Easy Maintenance

Diagnostic routines built into the UVAS plus sc sensor reduce the need for extensive calibration and maintenance. Only semi-yearly inspection and replacement of the wiper and seals is needed.

Application Drinking Water; Clear water
Cable Length 10 m fixed cable at sensor
Configurations Sensor only
Controller Sensor only
Diameter 70 mm
Length 333 mm
Maintenance Requirements 1 h/month in standard applications
Material Sensor enclosure: stainless steel 316, 1.4571, single sealed body
Wiper axle: stainless steel 1.4104
Cable gland: stainless steel 1.4305
Cable gland seal: PVDF
Profile carrier: stainless steel 1.4310
Wiper arm: stainless steel 1.4581
Wiper profile: Silicone
Measuring window: Suprasil (quartz glass)
Measurement method UV absorption measurement (unique 2-beam technique)
SAC 254 in accordance with DIN 38404 C3
Measuring Interval ≥ 1 min
Measuring Principle UV absorption measurement (patented 2-beam technique)
Measuring Principle 2
SAC 254 in accordance with DIN 38404 C3
Operating temperature range 2 – 40 °C
Parameter SAC
Path Length 50 mm
Pressure Range 0.5 bar
Range 0.01 – 60 1/m
Reference Wavelength 550 nm
Region US
Service Interval 6 months
User Maintenance 1 h/month
Warranty 12 months
Weight 3.6 kg
What’s included? SAC probe, user manual





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