The accuracy of detecting gas leakage in a fuel battery system is improved. The abbreviated data abstracts a complete path name corresponding to each one of the plurality of components. In one embodiment, the reduced pressure permits the piston to \u201cbottom out\u201d relative to the cylinder, which is a condition not otherwise achievable without the relief device. And then shut off the switch and carries out the test using the fault current which is produced by the fault current circuit. A second voltage independent of the first voltage is applied to the third electrode, thereby changing the optical properties.