The PCE-TUM 150 turbidity meter is a professional instrument for continuous online monitoring of water turbidity, designed for water treatment plants, filtration systems, drinking water quality control, direct fresh water and industrial processes where the presence of suspended particles must be constantly checked. It is suitable for fixed installations where measurement should not only be performed manually on samples, but continuously acquired and transmitted to an external evaluation, supervision or automation system.

The measuring principle is nephelometric and based on detection of light scattered at 90°. A tungsten lamp sends light into the water sample; suspended particles in the liquid scatter the light, and a silicon photocell detects the scattered radiation at a 90° angle. The measured value is converted into turbidity expressed in NTU. This method is particularly suitable for checking water quality after filtration, treatment and clarification processes because it can detect changes even at low turbidity values.

The PCE-TUM 150 has two measuring ranges to cover both very low turbidity and higher values. In the 0.001 ... 40 NTU range it offers 0.001 NTU resolution and ±2% of measured value accuracy. In the 40 ... 100 NTU range, resolution is 0.1 NTU and accuracy is ±5% of measured value. This dual management makes the instrument useful both for fine control of treated and filtered water and for monitoring water with a higher content of suspended substances.

The stated repeatability is ±2%, an important value for applications where process trends must be verified over time and successive readings compared. In a water treatment plant, measurement stability and repeatability help identify filtration anomalies, deterioration of outlet quality, variations in inlet load or problems related to maintenance, filter cleaning, chemical dosing and flow management.

Measurement takes place continuously during online operation. The measured values can be cyclically transmitted via RS485/Modbus interface to an external system such as a PLC, control panel, supervision system, data logger or plant monitoring platform. This makes the turbidity meter suitable for modern plants where water quality must be monitored in real time and integrated into automation or alarm processes.

The main application field is turbidity control in fresh water. The device can be used in drinking water systems, filtration systems, process water treatment, technical plants, quality control circuits, monitoring installations and systems where the presence of suspended particles must be kept within defined limits. It is particularly useful downstream of filters, membranes, clarification stages or treatment sections to verify that the process maintains the required quality.

The device requires a sample flow rate between 300 and 700 ml/min. This is essential for correct measurement because too low or too high a flow can influence reading stability, sample renewal and system response. During installation, it is therefore important to correctly adjust the flow, use the supplied fittings and maintain stable hydraulic feed, avoiding air bubbles, excessive pressure, improper restrictions or stagnant areas.

The scope of delivery includes a throttle valve with non-return function, straight screw fitting, pneumatic push-in fittings for tubing and water tubes for feed, drain and venting. These components facilitate connection of the turbidity meter to the hydraulic circuit and help manage sample inlet, outlet and venting correctly. The venting system is important because air bubbles in the optical path can alter measurement, generating unstable or non-representative values.

The IP65 protection rating makes the PCE-TUM 150 suitable for technical and plant environments where dust, humidity and splashes may be present. This does not mean the device should be immersed or subjected to aggressive jets, but it indicates adequate protection for many industrial and water treatment installations. It is still advisable to install it in a protected position, accessible for maintenance and away from impacts, vibration and excessive environmental conditions.

Power supply is 12 V DC, which facilitates integration into electrical panels, automation systems and installations with low-voltage auxiliary supply. Before connection, correct polarity, voltage stability and compatibility with the control system must be checked. Stable power supply contributes to measurement quality and continuous online monitoring.

The specified operating conditions are 0 ... 45 °C and 5 ... 95% relative humidity without condensation. Storage conditions are -15 ... 60 °C and 5 ... 95% relative humidity without condensation. These data must be considered during installation and plant management, avoiding internal condensation, freezing, overheating, direct exposure to heat sources and environments incompatible with measuring electronics.

Dimensions of 212 x 305 x 393 mm and a weight of 2533 g indicate a compact but structured instrument for technical installation. It is not a pocket meter, but a device to be integrated into a plant, close to a sampling line or control section. The 3 m connection cable offers flexibility in positioning relative to the panel or data acquisition system.

Calibration of the turbidity meter is carried out with software support via RS485/Modbus interface. The procedure involves setting the zero point with pure water at 0 NTU and then using a standard solution for adjustment. This procedure is essential to ensure reliable measurements over time, especially in quality control, process or drinking water applications where turbidity may be a critical parameter.

To maintain instrument accuracy, periodic cleaning and maintenance are important. Deposits, biofilm, scaling, dirt, sediment or bubbles in the measuring circuit can affect the reading. The design is described as easy to clean and simple to maintain, but intervention frequency should be defined according to water quality, suspended solids content, continuity of use and plant conditions.

In industrial use, the turbidity meter can be used to verify filter efficiency, check water quality downstream of treatment, monitor water in food or technical processes, supervise fresh water lines, check possible anomalies in drinking water systems and detect sudden changes in turbidity. Integration with external systems allows alarms to be set, data recorded, historical analysis performed and process management improved.

For correct measurement, it is advisable to install the device where the sample is representative of the process, with stable flow and no air intake. The line must be clean, fittings properly tightened and drainage correctly sized. Incompatible pressures, excessive vibration, stagnation and sample contamination should be avoided. In case of abnormal values, air bubbles, dirt, incorrect flow or need for recalibration should be checked first.

The scope of delivery includes 1 PCE-TUM 150 turbidity meter with 3 m connection cable, 3 M8 x 60 expansion plugs, 1 throttle valve with non-return function, 1 straight screw fitting, 2 pneumatic push-in fittings for tubing, 3 water tubes for feed, drain and venting, and operating instructions available in English and Italian translation. The equipment allows hydraulic and electrical installation to be prepared in a complete way.

The PCE-TUM 150 turbidity meter is therefore a reliable solution for continuous monitoring of turbidity in fresh water. The combination of 90° nephelometric method, measuring range up to 100 NTU, resolution down to 0.001 NTU, RS485/Modbus interface, IP65 protection, controlled flow rate 300 ... 700 ml/min, 12 V DC power supply and included installation accessories makes it suitable for water treatment plants, filtration, drinking water systems, quality control and industrial processes requiring continuous, repeatable data that can be integrated into supervision systems.