Electrical grounding is an important feature that increases the reliability, robustness, and safety of the installations. This rule also applies to instrumentation. However, installations with electronic instrumentation have some peculiarities and you need to pay special attention to the grounding process.  

The easiest and quickest way to obtain a grounding point is not always the best for electronic instrumentation. The first step is to use an earth conductor exclusively for the instrumentation.  

Poorly designed grounding can have undesirable effects on the performance of the instrumentation. The “ground loop” is one of these effects.

 

What is a ground loop? 

A ground loop is the undue flow of electric current through the ground. It is caused by the electrical potential differences (ddp) that appear along the grounding system. This undue circulation can cause measurement errors, malfunctions, or damage to electronic instrumentation equipment.  

While still in the design phase, the professional responsible must identify the points at which probable ground loops may appear and take preventive measures.  

NOVUS has signal conditioners that offer galvanic isolation between input and output, i.e., dedicated equipment for installations where this problem may arise. Installations using “grounded junction” thermocouples are a good example. 

 

In particular, the transmitter allows you to isolate 2 electrical circuits connected by a 4-20 mA current signal. Easy to use, it is an equipment that should certainly be in the briefcase of every instrumentation professional.

 

Abstract   

The incidence of ground loops is a problem for instrumentation installations. When proper grounding is not possible, you can use galvanically-isolated transmitters such as or . They isolate the parts between the sensor and the 4-20 mA signal. You can also use a signal conditioner, such as , which allows you to isolate 2 electrical circuits connected by a 4-20 mA current signal. 

 

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