Unless it is compensated for, the "zero" reading is the starting point for a gauge, which is measuring pressure. These measurements above atmosphere pressure are referred to as "gauge pressure" and are indicated as PSIG. Example of this would be that 100 PSIG equals 114.7 PSIA. Unless otherwise indicated or defined, the reference to PSI is usually taken to be PSIG.
Gas Discharge Display
In digital instruments, a numerical readout in which the digit segments are delineated by the glow of ionized gas. Also described as "plasma" or "gas plasma" display.
A continuously changing temperature as a function of distance.
A thermocouple construction where the junction is attached (grounded) to the sheath as contrasted to an ungrounded or exposed junction type.