www.hpmag.co.uk HYDRAULICS & PNEUMATICS September 2026 15 live-stream data for more permanent storage or additional analysis. It is also possible to control the unit remotely using the local area network (LAN) connection and the appropriate application software running on a PC or mobile phone. As technology evolves, the difference between dataloggers and digital hydraulic testers is becoming less distinct. Webtec’s latest digital hydraulic tester, for example, measures flow and flow direction, pressure and temperature, while also displaying hydraulic power and efficiency. Users can stream data to a mobile phone via Bluetooth for storage, analysis or report creation. Using fully electronic pressure sensors, the unit is again capable of monitoring short duration pressure peaks. It is perhaps the ability to diagnose intermittent machine or hydraulic system faults where dataloggers have become invaluable. The units illustrated in figures 3 and 4 include triggering capability whereby the unit can be left for long periods of time monitoring (but not storing) the input data. When a certain parameter exceeds a pre-defined level however, the unit triggers and stores not only the subsequent data signals but also the signal levels leading up to the trigger point. This enables ‘cause and effect’ analysis to identify where a sudden change in one parameter creates a corresponding change in another. A typical example might be diagnosing the continual failures of a hydraulic conveyor drive motor. If the motor lifetime is considerably less than normal expectations, then some machine occurrence is probably the root cause. In this case, an angled screen placed across the conveyor pushes oversized material to the side (figure 6). However, when a piece of material experiences a momentary jam under the screen, a pressure peak occurs in the motor as its output torque demand suddenly increases. It may be that the main system relief valve sits close to the pump output on the power unit located some distance from the drive motor. It therefore cannot respond quickly enough to limit the pressure peak. A conventional mechanical pressure gauge would unlikely spot an occasional pressure peak. However, fitting an electronic pressure sensor, such as illustrated in figure 1, would record a short duration pressure peak. Upon analysing the recorded data, it would thus indicate that the maximum pressure rating of the motor had been exceeded, giving a clue to the cause of the continual failures. The next step would be to identify the reason why the maximum pressure was exceeded, which could involve the use of a datalogger as shown in figures 3 or 4. Such units can be set to trigger whenever the measured property exceeds a certain value, also offering the ability to record the time of the event. By matching the time of the pressure peak with momentary jamming of the conveyor, it becomes possible to identify the root cause of the damaging pressure spikes. This would prompt suitable modifications, either to the screen itself or by adding a fast-acting pressure relief valve close to the motor. Hydraulic dataloggers have become indispensable tools wherever hydraulic system performance requires understanding, verifying or improving. From fault diagnosis and condition monitoring to prototype evaluation, commissioning and test bench development, they provide engineers with the reliable data needed to make informed decisions. For further information please visit: www.webtec.com Fig. 3: Mid-Level Datalogger Fig. 4: Top Level Datalogger Fig. 5: Digital Hydraulic Tester with Remote Monitoring Fig. 6:
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