How does digital control of a DH-65 work?

The digital control system consists of a digital controller, a 120 to 24-volt step-down transformer (to power the controller), a 40-amp main heater, a 25-amp steam element, and two 10-amp solid state relays for the recirculation fan. To avoid overheating, a 340-degree high temperature thermostat and contactor is used in the circuit between the 40A solid state relay and the heating element. The 120-volt current from the black and white cables of the terminal block is sent to the transformer, to the convection fan solid state relay, the smoke element semiconductor relay and the vapor element semiconductor relay. 208/240 volts from the terminal block go over the black lead to the contactor switch and the red lead is connected directly to a lead of the main heater. When “Cooking” is selected in the menu and the START button has been pressed, the digital controller sends 5 volts DC to the convection fan, heater, vapor element, and semiconductor elements of the smoke element. In addition, 120 volts are sent from port # 1 of the fan relay via the temperature limiter to the contactor coil connection. The purpose of the contactor is to prevent the smoker from overheating if the 40Ap Solid State Relay does not break the circuit. The Hi-Limit thermostat opens at 340 degrees and cuts off the power to the coil of the contactor, which cuts off the power to the main heating element.