Pressure measurement because atmospheric pressure is always changing and the reference in this case is fixed at 1 bar. To produce an absolute pressure sensor, the manufacturer seals a high vacuum behind the sensing diaphragm. If the process-pressure connection of an absolute-pressure transmitter is open to the air, it will read the actual barometric pressure. The SI unit for pressure is the pascal (Pa), equal to one newton per square metre (N·m or kg·m·s). This special name for the unit was added in 1971; before that, pressure in SI was expressed in units such as N·m. When indicated, the zero reference is
GNU Pascal GNU Pascal GNU Pascal (GPC) is a Pascal compiler composed of a frontend to GNU Compiler Collection (GCC), similar to the way Fortran and other languages were added to GCC. GNU Pascal is ISO 7185 compatible, and it implements "most" of the ISO 10206 Extended Pascal standard. The major advantage of piggybacking GNU Pascal on the GCC compiler is that it is instantly portable to any platform the GCC compiler supports. However since GPC is a frontend, it does have to adapt if major changes are done to GCC (like a major new version). Typically, new major versions are adopted