There are two possibilities:
- A routine accuracy check was not performed at the appropriate time. If the check did not occur, an accuracy check must be performed before subject testing can resume.
If there is a failed accuracy check, the device must be taken out of service until re-calibrated and checked by a properly certified Calibration Technician.
According to the U.S. DOT regulations (link below), unless you are properly trained and authorized to perform calibrations, you cannot place the instrument back into service. Contact Technical Services at 314-429-4000 for further assistance.