Troubleshooting methods for vacuum pressure switches not operating

When the vacuum pressure switch fails to operate, it can be investigated from several aspects such as power supply and electrical connection, pressure setting and sensor, mechanical structure and moving parts, environment and interference, as well as system correlation. The following is a detailed introduction:

Troubleshooting of power supply and electrical connections

Check the power supply: Confirm whether the power supply for the vacuum pressure switch is properly connected. Use a multimeter to measure the power supply voltage to see if it is within the voltage range specified by the switch. For example, if the rated voltage of the switch is 24V DC, the measured value should be close to this value. Excessive deviation may cause the switch to fail to work properly. At the same time, check if the polarity of the power supply is reversed. Some switches have strict requirements for the polarity of the power supply. Reversing it will directly result in no operation.

Check the connection lines: Inspect whether the connection lines between the switch and the power supply, as well as the control system, are loose, open or short-circuited. Check whether the terminal blocks are tightened and whether there is any oxidation or corrosion. If the terminal blocks are loose, the contact resistance will increase, affecting signal transmission. If there is an open circuit or short circuit in the line, the switch will not be able to receive the correct electrical signal. The connectivity of the circuit can be checked with the on-off range of a multimeter. For circuits suspected of being faulty, they can be reconnected or replaced.

Pressure setting and sensor troubleshooting

Verify the pressure setting values: Confirm whether the action pressure and reset pressure setting values of the vacuum pressure switch are correct. It might be due to the unreasonable set value that the current system pressure has not reached the action threshold. For example, if the normal working pressure range of the system is from -0.06MPa to -0.08MPa, and the action pressure of the switch is set at -0.05MPa and the reset pressure is set at -0.09MPa, the switch will not act under the current pressure. At this point, the set value needs to be readjusted according to the actual working conditions.

Detection sensor performance: The sensor is a key component for sensing pressure changes. If it malfunctions, the switch will not be able to accurately obtain the pressure signal. The sensor can be calibrated using professional pressure calibration equipment to check whether its output signal is consistent with the actual pressure. If the output signal of the sensor is abnormal, it may be that the sensor is damaged or aged, and a new sensor needs to be replaced.

Inspection of mechanical structure and moving parts

Check the mechanical structure: Inspect the mechanical structure of the vacuum pressure switch for any deformation, damage or jamming. For example, whether the casing of the switch is deformed due to external force squeezing, causing the internal components to fail to work properly; Are there any foreign objects stuck in the mechanical transmission components that affect the flexibility of the operation? You can gently shake the switch with your hand to feel if there is any abnormal loosening or jamming, and at the same time check whether the installation of each component is firm.

Test the moving parts: For mechanical vacuum pressure switches, it is necessary to check whether the moving parts, such as microswitches and diaphragms, are damaged or failed. The contacts of the microswitch may wear out and oxidize due to long-term use, resulting in poor contact. The diaphragm may lose its elasticity due to aging or rupture and be unable to sense pressure changes normally. The on-off status of the microswitch can be detected with a multimeter. For damaged moving parts, they need to be replaced in time.

Environmental and interference investigation

Evaluate environmental factors: Consider whether the working environment where the vacuum pressure switch is located has an impact on its performance. For instance, excessively high or low ambient temperatures may lead to a decline in sensor performance and affect the operational accuracy of the switch. Excessive humidity may cause the internal components of the switch to become damp, leading to short circuits or leakage faults. Check whether the working environment of the switch is within the specified temperature and humidity range. If it exceeds the range, corresponding protective measures need to be taken, such as installing heat dissipation devices and dehumidification equipment.

Troubleshoot interference sources: Check if there are any electromagnetic interference sources around, such as high-power motors, frequency converters, etc. Electromagnetic interference may affect the electrical signal transmission of the switch, causing misoperation or non-operation. The electromagnetic field intensity around can be detected by an electromagnetic interference detector. If there is strong interference, shielding measures can be taken, such as installing the switch in a metal shielding box or keeping it away from the interference source.

System association troubleshooting

Check the system pressure: Confirm whether the actual vacuum pressure of the system is within the measurement range of the switch. If the system pressure is abnormal, such as vacuum pump failure, pipeline leakage, etc., causing the pressure to fail to reach the action threshold of the switch, the switch will naturally not act. The system pressure can be directly measured using a vacuum pressure gauge and compared with the set value of the switch. In cases of abnormal pressure, it is necessary to troubleshoot system faults, repair vacuum pumps, and block leakage points in pipelines, etc.

Check the control logic: Verify whether the control logic related to the vacuum pressure switch is correct. For instance, in an automated control system, there may be program errors or improper logical Settings, which can result in the system being unable to respond accordingly even when the switch operates. The program code, wiring diagram, etc. of the control system can be viewed to check whether the input and output logic of the switch signal meets the design requirements.