The motor control center is housed in a steel structure, enclosed with metal walls, ceiling and floor. It is mounted on a concrete foundation and is separate from other buildings. It has HVAC (heating, ventilating and air conditioning).
These units are built by Astec and are similar to the control centers long used at HMA plants. They are prefabricated at the Astec factory and eliminate the problems associated with on-site fabrication and wiring of of such units.
The control center centralizes all electrical power for the terminal and for the motor controls. The controls are housed in a series of electrical racks and panels.
Electrical power is sub-divided into two independent control systems, one for the polymer blending system and another for all other electrical power.
The master computer and PLCs for the terminal are located in the motor control center. They control and monitor virtually all terminal functions.
They control the asphalt pumps used to transfer asphalt from one tank to another. Positions of the three valves on the outlet side of each asphalt pump can be verified on the computer screen before the pump is operated.
Client computers with multiple stations that monitor terminal functions are located in the terminal office.