TACHOMETER The SHD30 is a microprocessor-based digital tachometer with an hourmeter and an overspeed trip point. The trip point can be connected as either a form "c" relay output or as a normally open SCR output for alarm or shutdown on overspeed. The five-digit, liquid crystal display is updated every second. The SHD30 receives power and RPM data from either a magnetic pickup or a capacitor discharge (CD) ignition. The hourmeter is adjustable to a preset time and resettable to zero. Should power be lost, on-board batteries maintain the run hours display and allow for resetting the overspeed relay output. Approved for Class I, Division 2, Groups C & D hazardous areas. SHD30 digital tachometer and hourmeter by Murphy. Panel-mounting design Plastic enclosure (5-1/16 (129 mm) long 4-1/4 in. (108 mm) high) RPM data and power supplied by magnetic pickup or capacitor discharge (CD) ignition 3 to 666 Hz ignition frequency range: 1 to 10 kHz magnetic pickup frequency range 0 to 65535 hours hourmeter range