The Speed and Key Monitor is designed for high reliability for the plant's most critical rotating machinery monitoring speed, phase, zero speed and direction of rotation. This 1-slot monitor is used together with the AMS 6500 monitors to build a complete API 670 machinery protection monitor. Applications include steam, gas, compressors and hydro turbine machinery. The Speed and Key Monitor can be configured for redundant mode where automatic switchover from primary to backup latch is possible. Sensor gap voltage and pulse counting/comparison are monitored to trigger switchover. When the Speed and Key Monitor is operating in redundant mode, the main and follower key or speed displacement sensor must be installed in the same axial plane to ensure phase continuity upon failure. Speed measurements consist of a displacement sensor mounted radially to the machine with the target being a toothed wheel, a keyway or gear rotating on the shaft. The purpose of the speed measurement is to alarm on zero speed, monitor for reverse rotation and provide a speed measurement to track process conditions for advanced analysis. Key, or phase resolution target, also a toothed wheel or gear target but must have a once per revolution target, not a toothed displacement for a transducer. The phase measurement is a critical parameter when looking for machine health changes. The AMS 6500 is an integral part of PlantWeb™ and AMS software. PlantWeb provides operations integrated machinery health combined with the Ovation™ and DeltaV™ process control system. AMS software provides maintenance personnel advanced predictive and performance diagnostic tools to confidently and accurately determine machine malfunctions early. | 
