Computer control a number of relay application cases, you can go to see, is free This requires a PLC controller
When the change in the input amount (excitation amount) reaches the predetermined requirement, an appliance for changing the predetermined amount of the controlled amount in the electric output circuit is made. The relay is an electronic control device, it has a control system (also known as the input circuit) and the control system (also known as the output circuit), usually used in automatic control circuit, it is actually a small current to control the larger A "automatic switch" of the current. So in the circuit plays an automatic adjustment, security protection, conversion circuit and so on.
