What are the methods of self-diagnosis of computer control system online system failure

1. General principles of fault diagnosis

Analyze the problem is the premise of solving the problem, correctly analyze the fault is the premise of troubleshooting, most of the hydraulic system failure is not a sudden occurrence, there are always a precursor to the occurrence of failure, if the precursor did not draw attention to the precursor when the precursor to a certain degree of development of fault phenomena will occur. Caused by hydraulic system failure is caused by a variety of reasons, not no fixed rules can be found, but there are certain rules can be found. Statistics show that about 90% of the failure of the hydraulic system is due to the operator and the staff did not follow the provisions of the necessary maintenance and inspection of machinery and equipment. In order to quickly, accurately and conveniently diagnose the problem, we must fully understand the characteristics and laws of hydraulic failure, the following principles are worth following in the diagnosis of the problem:

1.1 check the working environment of the hydraulic system.

The correct working environment and working conditions is the premise of the normal work of the hydraulic system. Hydraulic system to work properly, the need for a certain working environment and working conditions for the platform, if the working environment seriously does not meet the standards of the normal work of the system, the system does not want to fail is almost impossible, so in the beginning of the diagnosis of the fault we should first determine and determine the working conditions of the hydraulic system and the peripheral environment is normal, for the working environment does not meet the standards and conditions of the corrections in a timely manner.

1.2 Judgment of the failure area.

According to the "barrel principle" we can easily know that the hydraulic system failure occurs because the weakest link in the whole system has a problem, so in the judgment of the failure part should be based on the failure phenomenon and characteristics of the region to determine the failure, gradually narrow the scope of the failure, targeted analysis of the failure The reason for the failure, and ultimately find out exactly where the fault is, so that the complexity of the problem is simplified.

1.3 Comprehensive analysis of the fault.

According to the above method to find the fault, it should be gradually in-depth to find a variety of direct or indirect possible causes. In order to avoid blindness, we must be based on the basic principles of the hydraulic system, targeted comprehensive analysis, logical judgment, minimize the object of suspicion gradually approaching, until the fault is to find out where the part.

1.4 The establishment of a perfect operating record.

Troubleshooting is based on operating records and certain system parameters. Establishment of system operation records, which is the prevention, discovery and treatment of faults in the scientific basis; the establishment of equipment operation fault analysis table, which is a high degree of experience in the use of summary, help to make a rapid judgment on the fault phenomenon; with certain detection means, can make accurate quantitative analysis of the fault.

Traditional diagnostic methods

Logical analysis of the step-by-step approximation method is to find the more traditional method of hydraulic system failure. This method is realized through a comprehensive analysis and condition judgment, that is, construction machinery maintenance personnel through the "see" "listen" "touch" "smell "and simple tests and understanding of the basic principles of the hydraulic system, with work experience to judge the reasons for the search for faults and failures. The specific practice of this method is when the hydraulic system failure, because the cause of the failure of many possibilities, generally using logical algebraic methods, the list of possible causes of failure, and then according to the principle of the first easy to be followed by the principle of logical judgment one by one, item by item approximation, and ultimately find out the cause of the failure.

This method for those experienced engineering and technical maintenance personnel, is a very effective method, because this method in the fault diagnosis process requires engineering and technical maintenance personnel with a wealth of basic knowledge of the hydraulic system and strong ability to analyze the problem of troubleshooting, in order to ensure that the diagnosis of the effectiveness and accuracy. But we can not see that this method of diagnosis process is more cumbersome, need to go through a lot of checking and verification work, and can only be qualitative analysis, diagnosis of the cause of the failure is not accurate enough, but also can not reduce the blindness of the system failure detection and dismantling of the workload, therefore, the traditional logical analysis of the step-by-step approximation method is far from being able to meet the requirements of the maintenance of modern hydraulic systems.

3. Fault diagnosis methods based on parameter measurement

With the gradual development of the hydraulic system to large-scale and automatic control direction, at the same time, a variety of fault diagnosis methods. Such as iron spectrum diagnosis and artificial intelligence-based expert diagnostic system, these methods, although the hydraulic system fault diagnosis brings broad prospects, but most of these methods require expensive detection equipment and complex sensing control system and computer processing system, is not adapted to the field to promote the use. The following introduces a simple, practical based on parameter measurement of the hydraulic system fault diagnosis method.

The essence of the failure of the hydraulic system is the abnormal change of the system parameters, so when the hydraulic system failure is bound to be a component of the system or some components have a failure, that is, a parameter has deviated from the prescribed value. Maintenance personnel need to deal with immediately. Then on the basis of parameter measurement, combined with logical analysis, you can quickly and accurately find out where the fault lies.

Parameter measurement method can not only diagnose the system failure, but also can predict the possible failure, and this prediction and diagnosis are quantitative, greatly improving the speed and accuracy of diagnosis. This test is a direct measurement, fast detection speed, small error, simple detection equipment, easy to promote the use of the production site. Suitable for any hydraulic system testing. Measurement, neither the need for downtime, and does not damage the hydraulic system, almost any part of the system can be detected, not only to diagnose existing failures, but also online monitoring, forecasting potential failures.