Patent ID: 7257740

Claim:
A method of detecting the ground offset of parts of a network system, more particularly of testing the ground contact between network control units, where data are sent and received over at least one bus system, characterized in [a] that in the idle state of at least one bus line ( 10 , 12 ) provided for receiving data and/or of at least one receiver line ( 24 ), after a predefinable first time period has elapsed, the level voltage ( 14 ) of this at least one bus line ( 10 , 12 ) is scanned and compared with at least one predefinable limit or reference potential value ( 80 ), [b] that if the limit or reference potential value ( 80 ) is exceeded, at least one ground error signal ( 82 ) is generated, and [c] that in dependence on the fact whether until a predefinable second time period has elapsed, which is started at the same time as the predefinable first time period and is longer than the predefinable first time period, [c.1] the idle state of the at least one bus line ( 10 , 12 ) or of the at least one receiver line ( 24 ) is still there, or [c.2] the idle state of the at least one bus line ( 10 , 12 ) or of the at least one receiver line ( 24 ) is no longer there, the ground error signal is acknowledged or not acknowledged, respectively.