What is the main difference between Industry 3.0 and Industry 4.0?

By the name, it can be understood that Industry 4.0 is the fourth industrial revolution which is an ongoing transformation in the industrial sector. To understand the difference between the I 3.0 and I 4.0 it is essential to understand what changes were introduced in each of the revolutions which the Industry underwent previously:

1. Industry 1.0: Industry 1.0 refers to the mechanization of work which our ancestors used to perform manually. Thus, it was after the introduction of steam which made the mechanization of work possible. E.g. Weaving Loom etc.
2. Industry 2.0: Industry 2.0 is the transformation which was brought about by the introduction of electricity in the various processes. This made the use of assembly lines possible. The first electric assembly line was built in 1870.
3. Industry 3.0: Now industry 3.0 was a huge leap ahead wherein the advent of computer and automation ruled the industrial scene. It was during this period of transformation era where more and more robots were used in the processes to perform the tasks which were performed by humans. E.g. Use of Programmable Logic Controllers, Robots etc.
4. Industry 4.0: The fourth era of the industry is the era of Cyber-Physical Systems (CPS). CPS comprises of smart machines, storage systems and production facilities capable of autonomously exchanging information, triggering actions and control each other independently. This exchange of information is done by the Industrial Internet of things (IIOT) in which thousands of sensors work real-time and transfer the data to a local server or a cloud server. Here the analysis of the data is carried out by developing predictive models which help the organization to anticipate some irregularities in the processes or systems so that action can be taken well in advance, as opposed to taking action when the processor system is broken down. This is called Predictive Maintenance, taking the required actions in advance is made possible help of the data which is captured by the sensors. This data is very huge and termed as Big Data. The data analysis helps the industries not only to maintain the processes but also to improve manufacturing processes, material usage, supply chain and life cycle management of the product.
5. Difference between I3 and I4: To put in simple words the basic difference being that the machines work autonomously without the intervention of a human in Industry 4.0. Whereas in the industry 3.0 the machines are only automatized. For example: Consider a CNC Milling machine, if the machine is in the era of Industry 3.0, the tool changes can be done automatically but the speed at which the spindle should run is to be observed by the operator and the corrections should be made by him. Similarly, if the machine is in the Industrie 4.0 the tool changes are automatic at the same time the spindle speeds and all other parameters essential to carry out the process are recorded by the hundreds of sensors present in the machine and the optimum settings are done on its own based on a large amount of data there is to compare and optimize the process.