A hydraulic data logger is an electronic instrument used to measure and record hydraulic system parameters such as pressure, flow and temperature over time. Unlike a conventional gauge, a data logger allows engineers to review how these values change during machine operation, helping them identify intermittent faults, pressure fluctuations and changes in system performance.

Hydraulic data loggers are commonly used for fault-finding, preventive maintenance, commissioning, pre-dispatch inspections and hydraulic test bench applications.

The Webtec HPM range provides solutions from the HPM110 digital pressure gauge with optional data logging to the HPM7000 multi-channel hydraulic data logger for more complex measurements and analysis.

A hydraulic data logger can capture changes in system performance that may be missed during a routine inspection. Intermittent faults can occur only under specific operating conditions, making them difficult to identify using a conventional pressure gauge or a single measurement.

By recording hydraulic pressure, flow or temperature over time, engineers can examine what happens before, during and after a fault occurs.

Webtec HPM data loggers allow measurements to be stored and analysed using HPMComm software. Reviewing recorded measurement curves can help identify unusual pressure fluctuations, changes in flow or pressure losses that may indicate a developing problem.

Pressure spikes can be identified using a digital pressure measuring instrument with peak-pressure capture or a data logger capable of recording rapid pressure changes. These short-duration pressure increases may not be visible on conventional gauges.

The Webtec HPM110 digital pressure gauge measures peak pressure using a 10 ms scan rate, allowing the maximum detected pressure to be displayed.

For more detailed analysis, the HPM5000 and HPM7000 offer high-speed data acquisition, enabling engineers to examine pressure changes over time using compatible sensors.

The appropriate recording interval and sensor response should be selected according to the duration of the pressure event being investigated.

Yes. A hydraulic data logger can be used with appropriate pressure and flow sensors to evaluate hydraulic pump performance under different operating conditions.

By recording flow and pressure simultaneously, engineers can examine how pump output changes during machine operation or under different loads. Comparing measurements over time can also help identify changes in performance.

Webtec's HPM4000, HPM5000 and HPM7000 support measurements from multiple sensors. HPMComm software allows recorded curves to be compared, helping engineers evaluate pump performance, investigate pressure losses and identify possible leakage.

This information supports fault diagnosis and helps determine whether further testing or maintenance is required.

Yes. Hydraulic data logging allows engineers to establish a record of system performance and compare measurements taken at different stages of a machine's operating life.

For example, recording pressure and flow during routine servicing provides reference measurements that can be compared with future tests. Changes in these measurements may indicate developing wear, leakage or performance deterioration.

Webtec HPMComm software, used with compatible HPM data loggers, allows recorded measurements from different dates to be displayed together and compared.

This can help maintenance teams identify changes in system behaviour before they develop into more serious equipment problems, supporting planned maintenance and reducing unnecessary downtime.

The parameters that can be measured depend on the HPM model and the sensors connected.

The HPM110 measures hydraulic pressure, including minimum, maximum and peak values. The optional data logger version also records pressure measurements over time.

The HPM4000 supports measurements such as pressure, flow and temperature, with tachometer sensors available for the SR version. It is available for either analogue Sensor Recognition (SR) sensors or intelligent digital CAN sensors, as explained in Question 9.

The HPM5000 and HPM7000 support a wider range of Webtec sensors for measuring pressure, flow, temperature, rotational speed (RPM) and contamination.

These instruments can also be used with compatible custom or third-party sensors. The HPM5000 supports external analogue sensors with signals such as 4–20 mA, while the HPM7000 supports analogue sensors and, with the appropriate input module, CAN communication including SAE J1939.

This flexibility allows engineers to record additional machine parameters alongside conventional hydraulic measurements.

The maximum measurable pressure depends on the instrument and the pressure sensor being used.

The Webtec HPM110 digital pressure gauge is available in versions rated for maximum working pressures of 100 bar or 600 bar, with corresponding US pressure-range versions rated at 1,450 psi or 8,700 psi. Its specified accuracy is ±0.5% of full scale.

The HPM4000, HPM5000 and HPM7000 use external pressure transducers, allowing the measurement range to be selected according to the application.

Webtec offers standard pressure transducers rated up to 1,000 bar (approximately 14,500 psi). For applications requiring measurements above this pressure, custom pressure transducers can be used with compatible data loggers through suitable 4–20 mA analogue or CAN interfaces.

For example, the HPM5000 supports external 4–20 mA sensors, while the HPM7000 provides additional CAN and analogue input options.

The pressure rating of the selected transducer and its compatibility with the data logger must always be verified before testing.

The appropriate HPM data logger depends on the number of measurements required, sensor compatibility and the complexity of the hydraulic testing.

• HPM110-DL: Suitable for straightforward pressure monitoring and recording where a compact, battery-powered instrument is preferred.
• HPM4000: An entry-level multi-sensor data logger for hydraulic servicing and fault diagnosis. Available in two versions: SR, which uses analogue voltage-based Sensor Recognition technology, and CAN, which uses intelligent digital sensors communicating via the CANopen standard.
• HPM5000: A mid-range data logger with a colour touchscreen, Webtec CAN sensors and additional analogue inputs, including compatibility with external 4–20 mA sensors.
• HPM7000: A modular data logger for more demanding diagnostic, test bench and R&D applications, offering extensive recording capacity and additional CAN, CANopen, J1939 and analogue input options. An optional analogue module also supports existing Webtec SR sensors.

For simple pressure checks, the HPM110 may be sufficient. Applications requiring simultaneous measurement of several hydraulic parameters will generally benefit from one of the multi-channel HPM data loggers.

The choice between SR and CAN is particularly important where sensors are already installed or available. The differences are explained in Question 9.

The main difference is the way the sensors communicate with the data logger.

The HPM4000 SR uses Webtec's analogue Sensor Recognition (SR) technology. The sensors transmit measurements using an analogue voltage signal, while the Sensor Recognition function allows the data logger to automatically identify the sensor type, measurement range and calibration information without manual configuration. The HPM4000 SR supports up to two sensors and four measurement channels, including tachometer measurement.

The HPM4000 CAN uses intelligent digital sensors that communicate over a CAN network using the CANopen standard. Measurements are converted into digital information at the sensor and transmitted to the data logger. CAN sensors can be connected along a common network, simplifying wiring and allowing automatic sensor identification. The HPM4000 CAN supports up to three sensors and six measurement channels.

Both versions have a backlit graphical display, data logging capability and USB connectivity for transferring measurements to HPMComm software.

Their environmental protection ratings also differ: the HPM4000 CAN is rated IP67, while the HPM4000 SR is rated IP54.

SR and CAN sensors are not directly interchangeable, so the appropriate version should be selected according to the sensors being used.

A sensor is the physical device connected to the hydraulic system, while a measurement channel represents an individual parameter being measured.

Some sensors measure more than one parameter. For example, a Webtec pressure transducer incorporating temperature measurement can provide two channels of information from a single sensor.
This distinction is important when selecting a multi-channel hydraulic data logger.

The HPM5000 supports up to six Webtec CAN sensors, providing a maximum of 12 CAN measurement channels. It also has two auxiliary analogue inputs, giving up to 14 measured channels, plus two calculated channels.

The HPM7000 base model supports up to 48 Webtec CAN measurement channels, with additional input options available through its modular design.

Yes. Selected Webtec HPM data loggers can calculate additional hydraulic parameters from measurements supplied by connected sensors.

The HPM4000 can display calculated values such as differential pressure and hydraulic power.

The HPM5000 supports two calculated channels, with functions including addition, subtraction, multiplication, hydraulic power, differential power and volume.

The HPM7000 supports further analysis through HPMComm software, including freely configurable calculation channels.

These capabilities are useful when evaluating hydraulic pump performance, investigating pressure losses or analysing how a system behaves under changing loads.

The appropriate measurement sensors must be connected to provide the values required for each calculation.

Yes, selected HPM data loggers support external analogue sensors, while the HPM7000 also offers additional CAN communication options.
The HPM5000 includes two auxiliary analogue inputs for measuring voltage or current signals, including 0/4–20 mA and voltage signals within its specified input range.

The HPM7000 can be equipped with an analogue input module that supports existing Webtec SR sensors, alongside configurable voltage or current inputs for external sensors. This provides compatibility with both Sensor Recognition equipment and other analogue measurement devices.

An optional CAN input module allows the HPM7000 to monitor external CAN networks, including CANopen and SAE J1939.

The HPM4000 SR and CAN versions are designed for their respective Webtec sensor types, so they should not be treated as general-purpose analogue or CAN/J1939 interfaces.

Sensor compatibility depends on the data logger, input module, electrical signal and communication protocol. For more information on the difference between SR and CAN sensors, see Question 9.

Yes. The Webtec HPM7000 is designed to support CAN-based measurements, including the ability to monitor external CAN communication networks.

The base model supports Webtec intelligent digital CAN sensors, which use the CANopen standard. It can alternatively connect to up to five external CANopen channels.

An optional CAN input module supports CANopen, generic CAN and SAE J1939 communication, including combinations of different CAN protocols.

The optional CAN module operates passively, allowing the logger to monitor signals already being transmitted on a CAN bus without supplying power to the connected sensors.

This makes the HPM7000 particularly useful for analysing hydraulic systems on modern mobile machinery where operating information is communicated electronically.

For applications using analogue voltage or 4–20 mA signals rather than digital CAN communication, the analogue input options described in Question 12 may be more appropriate.

The recording speed depends on the data logger, connected sensors and number of active measurement channels.

The HPM110 provides a 10 ms peak-pressure scan rate. Its data logger version uses adjustable recording intervals and automatic data compression for storing pressure measurements over longer periods.

The HPM5000 offers CAN sampling intervals of 1 ms with up to four sensors, or 2 ms with five or six sensors. Its auxiliary analogue inputs also support a fast mode with a 0.1 ms sampling interval.

The HPM7000 supports sampling from 1 ms.

For rapid hydraulic events, the sampling interval and response characteristics of the sensor should be considered together when selecting a measurement system.

Recording duration varies depending on the data logger, available memory, sampling interval and number of channels being recorded.

The HPM110-DL can store up to 10 recorded tests, each lasting up to 24 hours and containing up to 18,000 data points. Automatic data compression adjusts the recording interval to make efficient use of the available memory.

The HPM4000 has internal storage for one measurement containing approximately 15,000 data records. A 1 GB USB memory stick is supplied, with support for capacities up to 4 GB.

The HPM5000 is supplied with a 4 GB USB memory stick, while the HPM7000 provides 12 GB of storage and can record up to 16 million measured values per test.

For longer measurements, the data loggers can dynamically adjust the sampling interval, reducing the sampling rate as required to extend recording duration and prevent the available memory from filling during the test.

This allows engineers to undertake extended monitoring without continuously recording at the highest sampling frequency. The trade-off is reduced time resolution during longer recordings, so the sampling strategy should be selected according to the hydraulic behaviour being investigated.

Recorded measurements can be transferred to a computer for analysis, with the method depending on the HPM model.

The HPM110-DL transfers stored pressure data through a mini-USB connection in CSV file format.

The HPM4000 uses USB connectivity and Webtec HPMComm software for data transfer and analysis.

The HPM5000 and HPM7000 use HPMComm 7.6, which supports graphical analysis, zoom functions, filters, mathematical calculations and comparison of measurement curves.

HPMComm 7.6 is specified for Windows 10 and Windows 11 and allows measurements to be exported in CSV format.

This provides a practical way to review hydraulic performance away from the machine and maintain records of completed tests.

Yes. Webtec HPMComm software provides tools for documenting hydraulic measurements and generating reports or test certificates.

With the HPM5000 and HPM7000, recorded measurements can be transferred to HPMComm 7.6 and presented graphically. Measurement records can include dates, times and notes, making it easier to identify and compare individual tests.

The software also supports reusable certificate templates incorporating information such as a company name, logo and address.

These features can help service engineers document commissioning, maintenance and diagnostic work, as well as retain records for future comparison.

Yes. Selected Webtec HPM data loggers allow live measurements to be viewed through a connected computer.

The HPM4000 supports online measurement transfer through its USB connection and HPMComm software.

The HPM5000 can be connected to a PC or laptop via USB for live streaming of measurement data. HPMComm 7.6 also provides remote connection and control functionality.

The HPM7000 supports USB connectivity and offers additional remote monitoring and control through a LAN connection using a VNC remote desktop application.

These capabilities are useful when working on hydraulic test benches or when measurements need to be viewed from a position away from the data logger.

Yes. The Webtec HPM range includes portable instruments with protective housings and different environmental protection ratings.

The HPM110 standard digital pressure gauge is rated IP67, while the HPM110-DL data logging version is rated IP65. For the HPM110-DL, the IP65 protection applies when the mini-USB protective cap is fully secured.

The HPM4000 CAN is rated IP67 and the HPM4000 SR is rated IP54.

Both the HPM5000 and HPM7000 are rated IP65 and feature protective case surrounds.

The ambient operating temperature also varies by model, so the selected logger should be checked against the environmental conditions of the application.
 

The Webtec HPM range includes battery-powered instruments suitable for portable hydraulic testing, with some models also offering dedicated mounting arrangements.

The HPM110 uses two 1.5 V AA batteries, with a specified battery life of approximately 1,500 hours for the standard version and 600 hours for the data logger version.

Both HPM4000 versions use rechargeable lithium-ion batteries and offer more than eight hours of operation with two sensors connected.

The HPM5000 provides approximately five hours of operation with six sensors. It has a folding stand and VESA 75 × 75 mm mounting points.

The HPM7000 has a rechargeable lithium-ion battery, external power supply and VESA 100 × 100 mm mounting points, making it suitable for both portable and fixed test bench applications.

Hydraulic measuring equipment should be connected using appropriate pressure-rated sensors, fittings and test connections suitable for the system being measured.

The HPM110 can be fitted to a standard hydraulic test point for temporary testing or left connected for continuous pressure monitoring. It can be installed in any orientation, and the datasheet specifies that connections must be made by suitably qualified personnel.

The HPM110 is factory calibrated, with a calibration certificate available as a chargeable option. This must be requested when ordering and cannot be requested retrospectively.

To minimise uncertainty in recorded measurements, data loggers with analogue inputs should be periodically checked at the same time as their associated analogue-output sensors.

Checking the data logger and sensors together helps verify the accuracy of the complete measurement system, rather than considering individual components in isolation. This provides greater confidence in the recorded results, particularly where measurements are used for fault diagnosis, maintenance decisions or performance verification.