Martin Luther King's iconic I Have a Dream speech is full of allusions. Let's look at a few: Dr. King's speech (1963) was made 100 years after Lincoln's Emancipation Proclamation (1863) that freed all slaves in rebel territories.
There are a number of commercial packages you can use for such purposes. Comsol multiphysics simulation software is a general purpose physics modelling software package that I belive can deal with electromagnitism. The link to their website is http://www.uk.comsol.com. Ansys is another commercial vendor that provides a electromagnetic physics module. There website is http://www.ansys.com.
A Programmable Logic Controller, or PLC, is more or less a small computer with a built-in operating system (OS).This OS is highly specialized to handle incoming events in real time, i.e., at the time of their occurrence. PLC is primarily used to control machinery. Programs written for PLCs consists in simple terms on instructions to turn on and off outputs based on input conditions and the internal program. In this aspect, it is similar to a computer.