The ATC 314B is an economical multi-range solid-state TDR with two models; one for off-delay (delay-on-break) and one for interval-on-delay operation. With three dial-selected adjustable ranges, it provides any timing period between 0.035 and 100 SEC with excellent repeat accuracy even with wide changes in voltage, temperature and reset time.
OFF-DELAY MODEL: Presuming the AC line is energizing the unit continuously, when the start switch is closed the relay energizes, the pilot light goes on and the unit resets. Opening the start switch begins the timing cycle. A relaxation oscillator runs at a rate determined by the set pot. When the oscillator count is equal to the level set by the range switch, a digital count circuit is satisfied and the unit times out.
At time out, the timing circuit and relay are de-energized and the pilot light goes off. Closing the start switch resets the unit. After a power failure (or on first startup) the unit will go to the timed out condition (relay de-energized) until the unit is reset by closing the start switch to begin a new cycle.
INTERVAL-ON-DELAY MODEL: Timing begins when the start switch is closed; simultaneously the relay is energized and the pilot light goes on. Either a momentary/sustained start or a sustained start input can be used (see wiring). Reset is accomplished by de-energizing the unit. At time-out, the timing circuit and relay are de-energized and the pilot light goes off.