The invention relates to a method for monitoring a measuring instrument, in particular a flow meter and a measuring device for carrying out said method. The aim of said invention is to reliably avoid errors of measurement which are produced by an assembly error. The inventive method consists in calculating a characteristic value based on a chronological series s(t) of a signal measured by the measuring device by comparing said characteristic value with pre-registered reference values. A message based on said comparison which estimates the validity of the assembly of the measuring instrument is automatically generated.
