As the core equipment for testing the mechanical properties of materials, the stability and accuracy of electronic universal testing machines are directly related to the reliability of scientific research data and the control of product quality. However, during long-term use, various problems are inevitable with the equipment. This article aims to systematically sort out the common fault phenomena of electronic universal testing machines and provide an effective diagnostic approach and solution to help technicians quickly restore the normal operation of the equipment.

1、 Core principle: external first, internal second, simple first, complex second

Before starting the investigation, please keep this principle in mind. Most faults are not caused by damage to core components, but rather by external environment, improper operation, or simple connection issues. Following this principle can avoid unnecessary disassembly and maintenance costs.

Safety first: Before any troubleshooting and maintenance operations, please make sure to cut off the power to ensure personal and equipment safety.

2、 Common fault classification and solutions

The following categorizes faults into several types and provides detailed troubleshooting steps.

1. The device cannot start normally or initialization fails

• Fault phenomenon: No response when pressing the power switch, or software prompts "initialization failed", "hardware not found" and other errors after system startup.

• Troubleshooting steps:

1. Check the power connection: Ensure that the power cord is securely plugged in and the power outlet is energized. Use a multimeter to check if the power supply voltage is stable.

2. Check the emergency stop switch: This is the most easily overlooked issue! Confirm that all emergency stop buttons on the device are in the up (not pressed) state.

3. Check the connecting cables: Turn off the power of the computer and the host, unplug the data cables (such as USB, Ethernet, etc.) between the host and the computer again, and ensure good contact.

4. Restart the system: Turn off all power, wait for one minute, then restart and try to reinitialize.

5. Driver/software issues: Check if the testing machine controller is correctly recognized in the computer device manager. If there is a yellow exclamation mark, try reinstalling the driver. Reinstall the measurement and control software if necessary.

2. Abnormal force measurement (inaccurate indication, drift, jumping)

This is one of the most common and challenging problems.

• Fault phenomenon:

Large indication error: The deviation between the test result and the nominal value of the standard sample exceeds the allowable range.

Force drift: When the sensor is not under force, the force value displayed does not return to zero and changes slowly.

Force fluctuation: The displayed value is unstable and fluctuates significantly.

• Troubleshooting steps:

1. Sensor zeroing: Perform the "zeroing" operation of the force sensor in the software. Ensure that there is no contact between the fixtures.

2. Check installation alignment: Improper clamping of the sample or inconsistent installation of the fixture can cause lateral force, seriously affecting measurement accuracy. Reinstall the fixtures and specimens to ensure proper alignment.

3. Check the sensor range: Has a suitable force sensor been selected? Measuring small force values with a large range will result in decreased accuracy. On the contrary, it will damage the sensor.

4. Environmental interference: Check for strong electromagnetic interference, significant temperature fluctuations, or vibration sources around the equipment (such as large equipment operation).

5. Sensor itself issues: If the above steps are ineffective, the sensor may have been overloaded, damaged, or drifting. Measurement calibration is required. Use a standard force gauge for verification. If it is confirmed to be a sensor issue, contact the manufacturer for repair or replacement.

3. Abnormal displacement/deformation measurement

• Fault phenomenon: inaccurate displacement display or abnormal reading of deformation extensometer.

• Troubleshooting steps:

1. Displacement reset: Before starting the test, reset the displacement in the software.

2. Check the photoelectric encoder: For the displacement of the crossbeam, check whether the coupling of the photoelectric encoder connected to the screw is loose. Clean the dust on the surface of the encoder.

3. Extension gauge issue:

▪ Poor contact: Check if the extensometer blade is in good contact with the specimen and if the clamping force is appropriate.

▪ Zeroing and Calibration: Is it correctly zeroed before use? Has calibration been carried out on schedule?

▪ Signal line damage: The signal line of the extensometer is prone to internal breakage due to frequent bending. Check its connectivity.

4. Mechanical resistance: Check whether the screw and guide rail are well lubricated and whether there are any foreign objects stuck. Clean and add specialized lubricating oil if necessary.

4. Abnormal operation of the crossbeam

• Fault phenomenon: The crossbeam does not move, the moving speed is unstable, or there is abnormal noise when moving.

• Troubleshooting steps:

1. Emergency stop and limit switch: Confirm again that the emergency stop button has been released, and check whether the upper/lower limit switch of the crossbeam travel has been triggered incorrectly or damaged.

2. Drive system issues:

▪ Servo motor/driver malfunction: Check for any abnormal sounds during motor operation. If so, it may be due to driver parameter errors or motor damage.

▪ Transmission mechanism: Check whether the synchronous belt (or chain) is loose or slipping. Check for any gaps or wear between the screw and nut. Lack of lubrication is the main reason and should be maintained regularly.

3. Control signal: Set a low-speed movement command in the software and observe whether the crossbeam responds. If there is no response, the problem may lie in the control card or signal transmission.

5. Software and communication issues

• Fault symptoms: software unresponsive, stuck, communication interrupted, test data unable to be saved or abnormal.

• Troubleshooting steps:

1. Restart the software: Close the software and restart it.

2. Check communication connection: Re plug and unplug the communication cable, and try replacing a computer USB port or network port.

3. Operating system compatibility: Ensure that the measurement and control software is compatible with the computer operating system (such as Windows 10/11). Run the software as an administrator.

4. Reinstall software: If the software frequently reports errors or crashes, try reinstalling the software after backing up the original data and method files.

5. Virus system conflict: Ensure that the computer is not infected and close other software that may conflict with it (such as antivirus software for real-time protection).

3、 Establish a preventive maintenance system to prevent problems before they arise

Instead of passive maintenance, it's better to take the initiative to maintain. Establishing a simple maintenance plan can greatly reduce the failure rate.

1. Daily maintenance:

Keep the equipment clean and wipe off dust.

Check if the fixture is intact.

Perform a simple zero point check and operational check before use.

2. Weekly/Monthly Maintenance:

Check the lubrication condition of the transmission mechanism and replenish specialized lubricating oil in a timely manner.

Tighten all loose fasteners.

Run the equipment with no-load upper and lower limits and check if the function is normal.

3. Regular calibration:

Strictly follow the national metrological regulations (such as JJG 475-2008 "Verification Regulations for Electronic Universal Testing Machines"), conduct at least one overall metrological calibration of the equipment every year to ensure data traceability and accuracy.

summary

When there is a problem with the electronic universal testing machine, stay calm and gradually investigate according to the logic of "external first, internal second, simple first, complex second". Starting from aspects such as power supply, connection, and operation settings can often quickly solve most problems. For complex faults involving core sensors and drivers, or problems that cannot be solved after investigation, equipment manufacturers or professional repair service providers should be contacted in a timely manner to avoid secondary damage caused by improper operation.

Through scientific diagnosis and active maintenance, your electronic universal testing machine will be able to provide reliable guarantees for your quality control and scientific research work in the long run.