Operating manual for the miniservo-control tester

Ever since the implementation of servo-control units (regular and minimodels) with manometers at U. S. Geological Survey streamflow stations, the need for an effective and efficient servo-control unit tester has been paramount among field personnel. In numerous cases, servo-control unit failures were blamed on battery failures and vice versa. There was no valid instrument to definitively identify cause of failure, let alone properly diagnose the servo-control/manometer system. In 1983, two servo-control unit testers were developed and fabricated. One was mechanical in fabrication, operation, and serviceability; the other was electronic. The testers were extensively used and evaluated in Maine, Ohio, Kansas, and Louisiana under a wide range of environmental conditions. The consensus to integrate the best aspects of both testers into one instrument allowed the Survey to finally solve its long-time need for an effective, efficient servo-control unit tester. (USGS)