Measurement system and method for functional testing

The invention relates to a measuring system which consists of a measuring device (1), a further device (2) and a data transmission means (3) for transferring data bits between the measuring device (1) and the further device (2). The meter (1) in this case has a signal monitoring circuit (1.6) and a switching element (1.9, 1.10). The switching element (1.9, 1.10) being in electrical contact with a test potential source (1.11), in which a switching element state, the test potential source (1.11) in contact with the signal monitoring circuit (1.6) is. The signal monitoring circuit (1.6) is also connected to the data transmission means (3) in contact. The invention also relates to a method in which in a test mode a functional check of the measuring system is made by connecting a test potential.