Digital Hydraulic Diagnostic Instruments for Pressure, Flow, and Temperature

Frequently Asked Questions About Digital Hydraulic Diagnostic Tools

In hydraulic diagnostics, pressure, flow rate, and temperature often need to be considered together. Only by analyzing the interaction of these parameters can one assess how a hydraulic system behaves under defined operating conditions. Here, we answer frequently asked questions about digital hydraulic diagnostics and the use of HD-01 measurement systems.

• What is a digital hydraulic diagnostic tool?

  A digital hydraulic diagnostic device is a measurement system used to analyze key physical parameters in hydraulic systems.

  Depending on the connected sensor or measurement block, the Leitenberger HD 01 can be used to measure and digitally display, in particular:

  • Pressure
  • Volume flow or flow rate
  • Temperature.

  This means the system goes beyond simply measuring pressure with a pressure gauge.

• What metrics does the HD 01 track?

  The HD 01 is designed for three key hydraulic parameters:

  • Pressure in bar
  • Flow rate in l/min
  • Temperature in °C

  The base unit has two measurement channels. With the appropriate sensors, this allows for the measurement of up to six physical parameters: 2× pressure, 2× temperature, and 2× flow rate.

• Why should pressure and flow rate be measured together?

  Pressure and flow rate describe different characteristics of a hydraulic system.

  For example, a system may build up high or seemingly correct pressure even though it is not delivering enough hydraulic fluid per unit of time.

  Therefore, in the event of problems such as:

  • slow operational movements
  • low performance
  • performance drop under load
  • unusual pump behavior

  additional flow rate measurements can provide important information.

• What does the hydraulic pressure indicate?

  Pressure is generated by the resistance or load in the hydraulic system and is an important parameter for evaluating hydraulic power transmission.

  However, a pressure reading must always be evaluated in relation to:

  • Measurement point
  • Operating conditions
  • Load
  • System configuration
  • Manufacturer specifications.
• What does the flow rate indicate?

  Flow rate describes the volume of fluid that flows through a measuring point within a given time.
  
  It is expressed, for example, in liters per minute.
  
  Among other things, flow rate affects the speed at which hydraulic cylinders or motors can be moved.

• Why is hydraulic oil temperature important for diagnostics?

  Among other things, temperature affects the operating characteristics and viscosity of the hydraulic oil.
  
  An unusually high operating temperature can be an additional indication of problems in the system.
  
  That is why the HD 01 measures temperature in addition to pressure and flow.

• What are the flow rate ranges for the HD 01?

  Currently, various HD-01 sets are available for different flow rates.

  These include:

  • HD 01_Set_01: 7.5–75 l/min
  • HD 01_Set_04: 7.5–75 l/min
  • HD 01_Set_02: 15–300 l/min
  • HD 01_Set_03: 40–600 l/min

  This allows the measurement system to be tailored to hydraulic systems of various sizes and pump capacities.

• What is the difference between HD 01_Set_01 and HD 01_Set_04?

  Both sets have a flow measurement range of 7.5 to 75 l/min.

  The main difference lies in the pressure measurement range:

  HD 01_Set_01

  • Flow: 7.5–75 l/min
  • Pressure: up to 250 bar
  • Temperature: 0–125 °C

  HD 01_Set_04

  • Flow rate: 7.5–75 l/min
  • Pressure: up to 400 bar
  • Temperature: 0–125 °C

  Set 04 is therefore suitable for applications where higher system pressures must be taken into account at comparable flow rates.

• What are the measurement ranges for HD 01_Set_02?

  HD 01_Set_02 is designed for higher flow rates.

  Measuring ranges:

  • Flow rate: 15–300 l/min
  • Pressure: up to 400 bar
  • Temperature: 0–125 °C

  The measuring block has a G 1 1/4" threaded connection.

• What are the measurement ranges for HD 01_Set_03?

  HD 01_Set_03 is designed for particularly high flow rates.

  Measurement ranges:

  • Flow rate: 40–600 l/min
  • Pressure: up to 400 bar
  • Temperature: 0–125 °C

  The measuring block has a G 1 1/2" threaded connection.

• Which HD-01 set do I need?

  The selection is primarily based on:

  • expected flow rate
  • maximum system pressure
  • connection size
  • machine or hydraulic system
  • intended measurement task

  The measurement range should be selected so that the expected values fall safely within the permissible range.

  An unnecessarily large measurement range is not automatically the best solution.

• What does “automatic sensor detection” mean?

  With the HD 01, compatible sensors or measuring blocks are automatically recognized by the meter.
  
  This eliminates the need to manually configure the sensor data for each measurement.
  
  The measurement range and measured variable are displayed on the screen according to the connected sensor.

• Does the HD 01 need to be programmed before each measurement?

  Compatible sensors are detected automatically.
  
  This eliminates the need for time-consuming manual entry of sensor parameters for the supported sensors.
  
  Of course, the actual test setup and the selection of the correct measurement range or sensor must still be tailored to the specific application.

• What does “two measurement channels” mean?

  The base unit has two measurement channels.
  
  This allows it to process sensor data from two measurement setups or sensor groups.
  
  For each measurement channel, the physical quantities of pressure, temperature, and flow rate can be displayed.

• Can two parts of a hydraulic system be examined at the same time?

  With the appropriate sensors and measurement blocks, the two measurement channels can be used to record multiple measured variables or measurement points.
  
  This can be useful, for example, for comparative measurements within a hydraulic system.
  
  The appropriate combination depends on the specific diagnostic task.

• How accurately does the flow sensor measure?

  For the current HD-01 sets, the accuracy specified for flow measurement is 0.5% of the measured value.
  
  This means that the reference value differs from that used in pressure measurement, where accuracy is specified relative to the full-scale value.

• How accurately does the pressure sensor measure?

  For the current HD-01 sets, a pressure measurement accuracy of 0.5% FS is specified.
  
  FS stands for “Full Scale,” or the full-scale value of the measurement range.
  
  Therefore, the pressure measurement range should be appropriately matched to the actual application.

• How exactly is temperature measured?

  The current HD-01 sets are specified to have a temperature measurement accuracy of 2% FS.
  
  The temperature measurement range for the current sets is 0 to 125 °C.

• Are the HD-01 devices calibrated?

  The current HD-01 complete sets are offered with a factory calibration certificate included.
  
  This is particularly helpful for repair shops and service centers that wish to document the measurement equipment they use.

• Can measurement values be saved?

  Yes.
  
  The HD 01 allows for the storage or recording of measurement values.
  
  This means that hydraulic processes can be documented over a specific period of time, rather than viewed solely as instantaneous measurements.

• How does data logging work on the HD 01?

  Measurement values can be saved or transferred via the USB function.
  
  The recorded data can then be processed as a CSV file.
  
  This allows pressure, flow, or temperature trends to be analyzed after the actual measurement.

• Does the HD 01 require special analysis software?

  No complex specialized software is required for basic analysis of the stored measurement data.
  
  The measurement values are provided as CSV files and can be opened, for example, in Microsoft Excel or another suitable spreadsheet program.

• Can the measured values be analyzed in Excel?

  Yes.

  CSV files can be opened using Microsoft Excel, for example.

  This allows you to, among other things:

  • Display measurement values in a table
  • Compare measurement trends
  • Create charts
  • Examine maximum and minimum values
  • Document measurements.
• When is data logging particularly useful in hydraulic diagnostics?

  A recording can be particularly helpful if a fault:

  • occurs only after a prolonged period of operation
  • is temperature-dependent
  • occurs only under load
  • occurs intermittently
  • occurs during certain machine movements
  • is associated with pressure or flow fluctuations

  This way, the technician does not have to rely solely on a single instantaneous reading.

• Is it possible to tell if a hydraulic pump is worn out?

  The diagnostic device provides measurement values that can be used to assess the performance of a hydraulic pump.
  
  For example, pressure and flow rate can be compared under defined conditions.
  
  However, the device itself does not automatically issue a diagnosis such as “pump OK” or “pump defective.”
  
  The assessment is based on the manufacturer’s specifications and the hydraulic system as a whole.

• Can a hydraulic pump reach the correct pressure but still deliver too little flow?

  Yes.

  Pressure and flow rate are different measured quantities.

  That is why measuring pressure alone may not be sufficient for certain types of malfunctions.

  This is precisely where the advantage of a digital hydraulic diagnostic device for pressure, flow, and temperature lies over a simple pressure gauge.

• Can the HD 01 be used to simulate a load on the hydraulic pump?

  For such tests, Leitenberger offers the MBV 02_LR flow-limiting valve or flow controller.
  
  This allows a load on the hydraulic pump to be simulated and the flow rate to be variably controlled.
  
  This enables the system behavior to be analyzed under defined load conditions.

• What is the MBV 02_LR?

  The MBV 02_LR is a flow-limiting valve or flow regulator designed to complement hydraulic diagnostics.

  Key Technical Specifications:

  • Flow rate up to 340 l/min
  • Maximum pressure 350 bar
  • Maximum temperature 125 °C
  • Connection thread G 1 1/4"

  Leitenberger specifically recommends it as a supplement to the HD 01_Set_01 and HD 01_Set_02.

• Why is a flow controller used for diagnostics?

  Without a hydraulic load, certain faults may not be reproducible.

  A suitable control valve can be used to apply a specific resistance to the hydraulic system.

  This allows you to investigate how, for example:

  • pressure
  • flow
  • temperature

  behave as the load increases.

• When using a flow-limiting valve, is it necessary to pay special attention to the temperature?

  Yes.
  
  By throttling or limiting the flow rate, hydraulic power is converted into heat.
  
  The temperature should therefore be monitored during a load test, and the system's permissible limits must be observed.

• Can the HD 01 be purchased without the complete measuring block?

  Yes.
  
  The HD 01 is also available as a base unit.
  
  It can be used in conjunction with the designated measurement sensors or measurement blocks.
  
  For a test setup that is ready for immediate use and tailored to a specific volume flow range, the complete sets are generally easier to select.

• What's included in an HD-01 complete set?

  Depending on the model, the current complete sets include, among other things:

  • HD-01 measuring device
  • Measuring turbine or measuring block
  • Temperature sensor
  • Flow sensor
  • Pressure sensor
  • Charger
  • USB flash drive

  This provides the essential components for measuring pressure, flow, and temperature.

• Is the HD 01 powered by a battery or a rechargeable battery?

  The HD 01 features a built-in rechargeable lithium-ion battery.
  
  This makes the device suitable for mobile measurements on vehicles and machinery.

• Is the display lit?

  Yes.
  
  The HD 01 features a backlit digital display.
  
  This makes it easier to read the measurements even in low-light conditions.

• For which hydraulic systems is the HD 01 suitable?

  The system is designed for both mobile and stationary hydraulic systems.

  Typical applications include, for example:

  • Agricultural machinery
  • Construction machinery
  • Forestry machinery
  • Municipal machinery
  • Commercial vehicles
  • Material handling equipment
  • Industrial hydraulic systems
  • Test benches and stationary systems

  The required pressure, flow, and connection ranges are critical factors.

• Is the HD 01 suitable for agricultural machinery?

  Yes.

  Agricultural machinery has numerous hydraulic functions in which pressure, flow, and temperature can be relevant for diagnostics.

  In addition, for electronically controlled machines, a Jaltest diagnostic test for agricultural machinery and vehicles may be useful.

  This allows electronic and hydraulic diagnostics to be combined.

• Is the HD 01 suitable for construction equipment?

  Yes.

  Construction machinery also features extensive hydraulic systems with high pressures and, in some cases, high flow rates.

  For electronically controlled systems, mechanical-hydraulic testing can also be combined with the Jaltest Diagnostics for Construction Machinery and Off-Highway Vehicles.

• Is the HD 01 suitable for forklifts and industrial trucks?

  Generally speaking, yes, provided that the measurement ranges, connections, and hydraulic system are compatible with the specific HD-01 model being used.

  For electronically monitored industrial trucks, the Jaltest Diagnostics for Forklifts and Industrial Trucks can also be used.

• Can an electronic vehicle diagnostic system replace the HD 01?

  Not entirely.

  An electronic diagnostic system can, for example:

  • display error codes
  • sensor signals
  • ECU information
  • actuator statuses.

  The HD 01, on the other hand, measures actual physical parameters in the hydraulic circuit:

  • pressure
  • flow rate
  • temperature

  The two methods therefore complement each other when dealing with complex fault patterns.

• What is the difference between the HD 01 and a hydraulic digital pressure gauge?

  A digital hydraulic pressure gauge is primarily used to measure pressure.

  The HD 01 can also measure:

  • flow rate
  • temperature

  allowing for a more comprehensive analysis of the hydraulic system.

  A digital pressure gauge may be sufficient for a clearly defined pressure-related issue. For more complex performance or functional problems, the HD 01 offers significantly more diagnostic capabilities.

• What is the difference between the HD 01 and a digital hydraulic test kit?

  A digital hydraulic test kit focuses primarily on pressure measurements and combines one or more digital pressure gauges with hoses and adapters.

  The HD 01, on the other hand, is an electronic multi-parameter measurement system for pressure, flow rate, and temperature.

  Which system is more suitable depends on the diagnostic task.

• What is the difference between digital and analog hydraulic diagnostics?

  Digital systems such as the HD 01 offer additional features such as:

  • digital measurement display
  • automatic sensor detection
  • data logging
  • USB storage
  • subsequent analysis

  An analog hydraulic diagnostic device, on the other hand, does not require electronic measurement processing and is suitable for direct, rugged testing of pressure, flow, and temperature.

• For which types of businesses is the HD 01 particularly well-suited?

  The system is particularly well-suited for:

  • Agricultural machinery repair shops
  • Construction equipment service centers
  • Commercial vehicle repair shops
  • Forestry equipment service centers
  • Municipal equipment
  • Forklift and material handling equipment service centers
  • Mobile service technicians
  • Industrial maintenance
  • Hydraulic service shops

  It is particularly useful in situations where hydraulic faults cannot be reliably pinpointed by pressure measurement alone.

  You can find additional solutions under Test and Diagnostic Equipment for Hydraulic Systems.