Patent ID: 6507277
Filing Date: 2003-01-14
Classification: G08B

Abstract:
A method for determining a short-circuit between the line of a danger signalling system and a shielding enclosure for the line, the danger signalling system comprising:a multiplicity of detectors (M1 to Mn) and other line members, in case of need, which respond to at least one danger criterion and are connected to a two-wire line (line A), a control center connected to the line (line A), which has a voltage supply and a central processor in which the addresses of the detectors (M1 to Mn) are stored for individually addressing and polling the detectors (M1 to Mn) as well as a program for monitoring the status of the detectors (M1 to Mn), characterized by the following process steps: the shielding enclosure is connected to ground via a resistor (RA) of the testing unit, a stabilized-current source (IKA) of the testing unit generates a stabilized current (IA) on the line, a voltage measuring device measures the voltage drop at the connection of the line and provides the value measured to the testing processor, the testing processor calculates the resistance of the short-circuited line up to the short-circuit location (K1) and calculates the line length up to the short-circuit location (K1) from the parameters of the line.