A Common Day of my Life. PART 4. To produce the pieces, the production department has a kind of machines named “machine tools”, as lathes, grinding machines, milling machines and drill presses. While the production department does its job, I design the control system for the new machine, starting with the electropneumatic circuit. Sensors, actuators, and PLCs (Programmable Logic Controller) that will be required in the circuit control are purchased. Then, while the purchasing department gets the necessary control products of our suppliers, I design the control program for “the brain of the machine”, the PLC. That will make everything work automatically, from receiving the signal from each sensor to take actions with each actuator. The whole process, from analysis to implementation, takes weeks of hard work.