Industrial automation arguably dates back to Henry Ford’s installation of a moving assembly line for the Model T in 1913; it is the use of various control systems to operate industrial equipment such as machinery, manufacturing processes and material handling equipment, with little or no human intervention.

Automating industrial processes has a number of benefits: it saves energy and materials; it improves the quality, accuracy and precision of industrial processes; it allows operation in hazardous environments (in nuclear plants, for example); and it vastly saves on labor.

The results are impressive

The Connected Factory and the Internet Of Things

The next stage after automating individual industrial processes is to make sure that they all work together smoothly – and provide data to their human masters, of course! The modern automated factory therefore relies on an industrial network using one of the numerous automation protocols such as Ethernet, Fieldbus, or HART Protocol to provide connectivity at the factory level.

Galvanic Isolation and Industrial Automation

Adding electronic control and connecting multiple systems together via a network has many benefits, but there are issues and challenges, too. One of these is the challenge of combining high-voltage, high-current machines such as industrial robots and CNC machines with low-voltage, low-current data acquisition systems and networked communications. We’re going to talk about an important technique used to battle this problem –galvanic isolation.

Galvanic isolation is the technique of isolating functional sections of electrical systems to prevent current flow between them; no direct (i.e., resistive) conduction path is permitted. Although there’s no resistive path between sections, power or information is still transferred by capacitive, inductive, optical, or other techniques.

Why is galvanic isolation needed in industrial automation?

Safety – Protecting users of electrical equipment from potentially lethal voltages and currents is a key requirement in any electrical design

Ground Differences & Ground Loops- Unlike the simple schematics we drew in school, as practicing engineers we soon learn that ground is most certainly not the same at different points in a system, especially when those systems are widely separated – between different parts of an industrial plant, say. This can lead to errors or even failure in a digital network because any difference in the ground reference

Common-Mode Voltages – in many cases we need to extract a small signal riding on top of a larger common-mode voltage: an in-phase signal or voltage that appears simultaneously on both input terminals. In some cases, this can offset the signal being measured

A number of regulatory standards govern isolation for industrial applications, including IEC 60204; UL508; UL60947, and CSA 14-10. In addition, IEC 61010-1 and VDE 410/411 cover industrial control.