For the daily regular verification of the test device, a blackbox (test dummy) is used, which is connected to the test device. It is checked whether the measured values determined by the test device match the values of the blackbox. If this is not the case, the test device is locked. The use of the device is only released again when a black box test with a correct result has been performed. Since we only supply digitally evaluating test devices, we usually do not perform this test with a "GO/NO-GO blackbox", but instead use only one blackbox and evaluate the resulting measured values within narrow tolerance limits.

Should a black box test end with a NO-GO test result (not in order), the test device is locked. In this case, the cause for the deviation of the measured values must be sought and eliminated. Only with a GO test result (GO) will the test device be released for use.

When the black box test is performed can be configured differently for the test devices. This can be time-controlled or quantity-dependent. Usually, the black box test is performed after switching on the test device.

Each blackbox consists of a Connection option to the test device and one or more precision resistors and/or inductances. It can be designed either for one test method or for combinations of several test methods.

To enable correct setting of the black box test steps, each blackbox is supplied with the resistance values and a calibration certificate.

The black box test is in accordance with the harmonized European procedure for factory surveillance and inspection according to CIG 021 and CIG 023.
CIG 021: Factory Inspection Procedures – CIG 021 specifies how inspection is carried out.
CIG 023: Factory Inspection Report – CIG 023 documents what was found during the inspection.