Implementation Phase 1 - Unit Automation
The first step in integration requires that some level of plant automation has taken place. It is important to build your automation system using highly reliable industry-hardened PLC's and automation equipment. The automation system should be based on non-proprietary based controllers/software and the PLC's and HMIs should be Ethernet capable devices. The data received at the Business Information Systems is only as good as the devices wired to the PLCs, in other words, if the transmitter of a particular parameter is faulty, then there is no use sending that particular parameter since it is not accurate. So we have to eliminate all possible sources of error in the field devices and automation equipment

Implementation Phase 2 Process Cell Automation
Once the basic automation is in place, the next step is to install PLCs/HMIs to control different process cells. Each cell would be a logical or geographical grouping of equipment or area of the plant. For example, a typical flour mill may be broken into the follow process cells:

Elevators/Storage Cleaning House Flour Mill Flour Storage/Loadout By-Products Storage/Loadout

Each process cell shares information with one another over the Ethernet Network. The different process cells work together over the common network as one automated production system. This is a network of PLCs communicating through Ethernet.