Abstract: In an apparatus for process analysis, a test substance is removed from the process stream by a probe and fed to an analysis instrument with a measured value display. Upstream of the analysis instrument, the test gas is conveyed through condensers. A monitoring unit is coupled to the analysis instruments and the processing chain without influencing the flow of data from the analysis instrument to the measured value display. The monitoring unit receives information about the entire apparatus via status sensors which are incorporated into the processing chain and into the analysis instrument. Depending on this information, the monitoring unit can intervene via solenoid valves, switches and motor potentiometers into the apparatus and alter its operation. The condition of the apparatus can also be displayed.