PROCESS MEASURING DEVICE

A process measurement device (1) with a measuring unit (2) for converting a variable to be measured into an electrical measurement signal (3) and a signal processing means (4) for processing the measurement signal (3) into a continuous sequence of digital measured values (5) further has a data compression means (11) on, the digital measured values (5) for the purpose of archiving in a memory means (15, 16) compressed, wherein difference values between the measured values (5) and an expected value (12) determined and are variable-length coded. Here the fact is used, that process - or process installations usually be regulated around a working point, so that the expectation values can be given for parameters to be measured, from which the measured values supplied by the measuring devices to process the measurements deviate or vary only within a rare value range.