Browse Prior Art Database

Power Off Timer

IP.com Disclosure Number: IPCOM000083486D
Original Publication Date: 1975-Jun-01
Included in the Prior Art Database: 2005-Mar-01
Document File: 2 page(s) / 37K

Publishing Venue

IBM

Related People

Kennedy, PJ: AUTHOR

Abstract

In processing operations which are monitored or controlled or both, by a data processor, it is normally necessary to know the duration of a power outage affecting both the process and the processor so that the process controls may be properly reset and the data processor updated.

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Power Off Timer

In processing operations which are monitored or controlled or both, by a data processor, it is normally necessary to know the duration of a power outage affecting both the process and the processor so that the process controls may be properly reset and the data processor updated.

The drawing illustrates an outage timer which may be used for such signaling. In the circuit, an input lead 1 is powered for so long as the main power is present. An inverter 2 has the voltage of its output line 3 depressed by the signal in lead 1. A clock 4 driven by an auxiliary power source 5 will have its signal passed through an AND 6 by the signal on line 3 to operate a counter 7 while the process power is down.

A flip-flop 8 will be set by the signal on line 3 to activate an outage signal line 9 on power loss, and this outage signal on line 9 together with the power present signal on line 1 are combined in AND 10 to set a flip-flop 11 when power is restored after an outage. A pulse on line 12 from the processor will reset counter 7 and flip-flops 8 and 11 when data processing is resumed.

In operation, whenever the main power goes out, line 3 will receive a signal to set flip-flop 8 and to start and keep counter 7 running. When power is restored on line 1, counter 7 is stopped and flip-flop 11 is set. The signal on line 13 to the processor from flip-flop 11 will interrupt the processor to initiate a recovery operation, during which the setting of counter 7 will be r...