Browse Prior Art Database

Multiple Fault Indicating System

IP.com Disclosure Number: IPCOM000076889D
Original Publication Date: 1972-May-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 41K

Publishing Venue

IBM

Related People

Driscoll, CD: AUTHOR

Abstract

This circuit is a replacement for the conventional relay circuits used to power down a processor when a fault or dangerous condition is detected. In the diagram, a central processing unit (CPU) power-off circuit 1 is normally closed through a manual switch 2 and contacts 3 of a relay 4. Energization of relay 4 will open switch 3 to turn off the processor.

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Multiple Fault Indicating System

This circuit is a replacement for the conventional relay circuits used to power down a processor when a fault or dangerous condition is detected. In the diagram, a central processing unit (CPU) power-off circuit 1 is normally closed through a manual switch 2 and contacts 3 of a relay 4. Energization of relay 4 will open switch 3 to turn off the processor.

Relay 4 can be energized by any of a plurality of fault detecting circuits of which three are shown. Each circuit uses a silicon-controlled rectifier (SCR) turned on when a switch is operated. Circuit 5 has an indicator lamp 6 and an SCR 7 in series between a voltage supply lead 8 and ground. A resistor 9, a normally open switch 10 and a resistor 11 are also connected in a similar series circuit, with the gate of SCR 7 connected to the junction of switch 10 and resistor
11. Any closure of switch 10 will apply a firing voltage to SCR 7 to light indicator
6. A second circuit 12 also has an indicator 13 and an SCR 14 in series from lead 8 to ground, and has a resistor 15 and a normally closed switch 16 also in such a series circuit. The midpoint of the resistor switch circuit is connected through a resistor 17 to the gate of SCR 14. As long as switch 16 is closed, the gate of SCR 14 is grounded and the SCR 14 does not fire until the switch 16 is opened.

The third circuit 18 also has an indicator 19 and an SCR 20 in series. The control circuit is a resistor 21 and a normally open swi...