Automated Alarm Program for HP5071A Frequency Standards

摘要

In the 1997 PTTI paper titled 'Maintenance of HP 5O71A Primary Frequency Standards at USNO,' Chadsey and Kubik presented findings to that date on USNO's efforts to evaluate the devices' performance according to their internal operational parameters. This paper presents methods used to evaluate those parameters and automatically detect abnormal operation. Some of the developmental difficulties will be discussed, as will some general guidelines on the tolerances USNO uses to detect problems with the HP 5071A frequencies standards. The importance of monitoring of the operating parameters of the HP 5071A cesium frequency standard was covered in a 1997 PTTI paper by Chadsey and Kubik. It was noted that by having a computer periodically inquire and permanently file the 22 parameters via the RS-232 connection, one could diagnose and in some cases predict the device's failure. All the data analysis was performed manually when that first paper was written. Manual analysis may be acceptable for some locations which have only a few HP 5071 A devices, but when five or more devices are involved, the personnel costs go up very quickly. The need to regularly look at the parameters for over 40 devices at USNO in Washington, DC drove the development of automating the data analysis toward an alarm system. Warnings were to be issued whenever a device exhibited abnormal behavior.