The 365C300Q30PX is a computing Digital Timer with three rotary knobs for setting and adjustment of the preset. The Preset can be any three-digit value from 0.01 seconds to 999 hours. The decimal and range are switch selectable. The high-intensity blue vacuum fluorescent display is DIP switch selectable to time-up or time-down. Two heavy-duty 7A DPDT relays provide instantaneous, interval or delayed output control. Plug-in panel mounting allows easy replacement without the removal of field wiring. Through its internal microcomputer, it keeps track of the set point throughout the time cycle. Whenever there is a change in set point, even during a cycle, it instantly re-computes the time remaining and accurately determines time-out. This unique capability is especially valuable in the time-down modes as it allows you to shorten a cycle without loss of accuracy. The timer has formidable defenses against noise: transformer power supply, full-wave bridges, buffered logic.