Profile: P M D Scientific, Inc. is a manufacturer of seismometers. Our product line includes accelerometers, force-balanced rotational seismometer, motion recorders, data loggers, seismic sensors and digitizers. Our seismometer does not require any mass locks, mass centering and special installation equipment and procedures, & it is waterproof up to one meter depth. Our seismometers BB603 contain micro-controllers which generate internally calibrating sine and other wave signal, and the calibration can be initiated by applying a logic level to the calibration enable input.