WTW digital IDS pH electrode SenTix 940-3, plastic shaft, 3 m fixed cable, 103741

The WTW SenTix 940-3 digital IDS pH electrode is intended for pH measurement in a wide range of laboratory, pilot plant and field applications. Designed for flexible operation with WTW IDS multiparameter meters, this digital electrode enables reliable signal transmission and documentation. Thanks to its extra-long, integrated 3-metre cable, this model is very well suited to measurements in hard-to-reach locations, deep tanks, open water bodies or larger experimental installations.

Intelligent IDS sensor technology and digital signal processing

The SenTix 940-3 uses IDS (Intelligent Digital Sensors) technology. Unlike conventional analogue probes, the sensitive analogue voltage signal is digitised and calibrated directly within the internal sensor assembly. This transient signal processing reduces electromagnetic interference that might occur along the longer cable run. An integrated data storage module permanently records the sensor’s specific serial number and a calibration history for up to 10 calibrations. Thanks to the intelligent QSC (Quality Sensor Control) function, the sensor continuously assesses its current status and displays this directly on the measuring instrument, supporting process reliability with every measurement.

Low-maintenance gel electrolyte and robust materials engineering

The material design is consistently optimised for mechanical durability and minimal maintenance intervals. The electrode features a plastic shaft made of PPE/PS, which protects the glass membrane against mechanical impact during field measurements or when immersed in deep tanks. A tried-and-tested gel electrolyte, combined with a fibre diaphragm, serves as the reference system. This low-maintenance system eliminates the need to top up liquid KCl electrolyte and reduces the risk of diaphragm blockages, which significantly extends the sensor’s service life in multi-user operation.

Integrated temperature compensation and extended 3-metre fixed cable

To ensure thermodynamically correct measurement results, the SenTix 940-3 features a built-in 30 kOhm NTC temperature sensor, which provides automatic, real-time temperature compensation of the pH value. Connection to the IDS meter is via the permanently fitted, 3-metre-long cable with a waterproof, digital IDS connector. The IDS plug connection is watertight and locked. The 3 m cable allows measurements at spacious laboratory workstations or during mobile outdoor use.

Technical details

Measurement & sensor technology

• Sensor type: Digital IDS pH electrode
• Model: SenTix 940-3
• pH measurement range: 0 to 14 pH
• Temperature element: Integrated NTC 30 kOhm temperature sensor
• Operating temperature range: 0 to 80 °C
• Calibration memory: Integrated memory for up to 10 calibrations
• Sensor rating: QSC-compatible (Quality Sensor Control)

Design & dimensions

• Shaft material: Plastic shaft (PPE/PS)
• Electrolyte: Low-maintenance gel electrolyte
• Diaphragm: Fibre diaphragm
• Shaft length: 120 mm
• Shaft diameter: 12 mm
• Connection type: Fixed cable, length 3.0 m with digital IDS plug
• Serial number: Stored electronically in the sensor

Operating conditions

• Maintenance: Low maintenance (no need to top up liquid electrolyte)
• Application: General aqueous media, laboratory and field measurements, deep sample vessels, environmental measurement technology

Scope of delivery

• 1 x WTW SenTix 940-3 digital IDS pH electrode with 3 m fixed cable (MPN: 103741)
• 1 x wetting cap with storage solution

Important note: pH buffer solutions, cleaning concentrates and the IDS meter itself are not included in the standard scope of delivery and must be ordered separately.

Individual requirements & accessories

To realise the full potential of the WTW SenTix 940-3, we recommend using it with a compatible WTW MultiLine or inoLab IDS meter. For regular recalibration and to safeguard the metrological chain, we offer WTW technical buffer solutions (pH 4.01, pH 7.00, pH 10.01) in our range. For the proper storage and care of the sensitive glass membrane, we recommend the original KCl storage solution. Please use our technical procurement service to put together your digital measuring station.