A Design Of The Automatic Gauging System Based On HART Protocol For Storage Tanks

In order to accelerate gauging technology for storage tanks toward automation in our country, it is necessary to develop the automatic gauging system for storage tanks. The system should be required low cost and high accuracy. In this paper, the core of the technology is discussed, which includes HART communication protocol, measurement methods and computation for storage tanks. HART communication protocol is applied in the system. The HART protocol provides a uniquely backward compatible solution for smart instrument communication as both 4~20mA analog and digital communication signals are transmitted simultaneously on the same wiring. HART provides many benefits by fieldbus, while remaining the compatibility and familiarity of existing 4~20mA systems. In this paper, HART protocol is illustrated, its FSK Physical Layer specifies the transmittal manner signal and voltage of signal. Data Link Layer specifies the device type and data transport protocols. The Command Layer specifies the HART Command Set and Response codes. The basic composition and functions of the Processor for Tank Farm conforming HART protocol are introduced concretely. The operational principles of hardware and software of the Processor for Tank Farm are described.