Grounding and shielding are an essential part of industries. Inappropriate grounding poses some serious dangers to equipment operation and working system. Industrial automation projects must take consideration of the standards that guarantee adequate signal levels, in addition to the safety demanded by the application.
Poor or inadequate grounding may lead to electric shocks to users and results in operational problems like communication failures, excessive EMI generation, abnormal heating on the powering stages, frequent computers locking, burning of electronic components, etc. However, by making use of proper installation methods, adequate techniques of projects, cable distribution, proper grounding and shielding, the potential dangers and noise effects can be controlled.
The problem of electromagnetic compatibility arises due to the presence of equipment of different technologies and inadequate installations which emits electromagnetic energy. Equipment suffers adverse impact from EMI energy, which usually results from circuit breakers, sparking on the motor brushes, tension circuits switching, atmospheric discharges or electrostatic discharge between persons and equipment, microwaves devices, or mobile communication equipment.
You can bear the risk of neglecting and being irresponsible and incompetent in technical problems. Therefore, consider the following points for proper shielding and grounding in Industrial Automation.
- It is important to control internal and external electromagnetic interference. In automation systems, controlling noises play a crucial role as it may become a serious problem even when best devices and hardware are put to use. Simple devices and techniques, such as the use of adequate grounding methods, shielding, twisted wires, filters, and differential amplifiers can be used to control noise.
- To provide protection against lightning and EMI, as well as, fulfill the safety standards; the grounding system should be a zero impedance plan. The mixture of different current levels will help in making the systems free from interference.
- To control the EMI effects, take into account the topology, the distribution of the wiring, types of cables, and protection techniques. Thus, you have to ensure that the connections are in proper working conditions and check for inactive connectors as they may develop resistance or become RF detectors.
- The performance of the system is also affected by inappropriate installation or use of equipment in non-recommended applications which often leads to accidents. Therefore, employing trained and qualified professionals on installation, operation and maintenance jobs is essential. Poor installation destroys the reliability of a control system which involves problems in cables, their courses, packing, shielding, and grounding.
- Every plant and system has its own safety details, so it’s better to refer to the physical regulations and the safety practices for each area. Make sure to work safely on measurements and to prevent electric shock from high voltage avoid any contact between terminals and wiring.
- In terms of process industry, grounding can be classified into three types, that is, Dirty grounding, Clean grounding, and Structural grounding. Moreover, to provide protection against electric shock, chassis or housing grounding is used.
- Inappropriate grounding and shielding are responsible for producing noise in power source lines. EMI leads to various problems, such as gradually damaging the equipment and its components; communication failures; producing alarms without explanation, and burning of electronic components, etc. In industries and factories, the problems of overload, sub-voltage, or peaks are very common because functioning of the larger machines, like welding instruments, motors (MCCs) and digital networks and computers results in frequent EMI.
- Proper shielding and grounding ensure best working system, as well as, safe work place. Most of the shielding and grounding problems are related to measurement errors, which can be traced back to currents from external fields that have become coupled into the measurement test leads.
- Another important factor is taking preventive maintenance actions every year. Check the quality of each connection on the grounding system to determine its robustness, reliability and low impedance, as well as, make sure that it is free from contamination and corrosion.