The invention relates to a microwave excited ultraviolet lamp system with a data logging and retrieval circuit and a method for operating the same. The data logging and retrieval circuit stores operational data in a cache memory using a FIFO data storage protocol. The contents of the cache memory are periodically copied to a larger removable memory so that the removable memory contains a relatively long historical record of the system operational parameters. The data logging and retrieval circuit includes a data port configured to load the contents of the cache memory into an external device when the device is coupled to the data port. A second data port allows the external device to supply power to the data logging and retrieval circuit so that data may be retrieved when the internal power supply is malfunctioning. Data stored in the removable memory may be protected so that it may only be accessed by authorized personnel.