Columbia Research Laboratories’ Model VM-300 vibration meter is a general-purpose vibration measuring instrument designed for periodic routine checks of industrial equipment where portability and ease of use are required. Acceleration, velocity, and displacement measurement modes are provided. Dual power allows the meter to be powered from its internal battery in the field or from an external AC adapter to save battery life in bench applications. A precision low-voltage lockout circuit prevents the meter from making erroneous readings due to low battery. An automatic, 10-minute timeout during battery operation will not allow the meter to drain the battery while unattended. An optional printer can be connected to the meter for permanently recording measurements. The meter operates from a rugged, precision piezoelectric accelerometer and incorporates a charge amplifier input stage for stability and minimizing errors. Operation is controlled by an internal, integrated micro-controller, acting under direction of a splash-resistant, seven-key membrane keypad. The sensor probe contains Columbia’s piezoelectric accelerometer, which outputs an electric charge proportional to the instantaneous value of the applied acceleration. This charge signal is communicated to the instrument through a low-noise coaxial cable. The meter is housed in a 7.5-inch by 4-inch by 2-inch plastic case with detachable probe and is supplied with a padded carrying case and AC adapter. –