CIRCUIT FOR AND METHOD OF MULTIPLEXING FOR MONITORING A PLURALITY OF SEPARATE MACHINE TOOLS

• US 3,641,326 A
• Filed: 11/22/1968
• Issued: 02/08/1972
• Est. Priority Date: 11/22/1968
• Status: Expired due to Term

• Current Assignee: Robert B. Harte
• Original Assignee: Robert B. Harte
• Inventors: Harte, Robert B.
• Primary Examiner(s): Ruggiero, Joseph F.
• Application Number:
  US04/778,263
• Time in Patent Office: 1,173 Days
• Field of Search: 235/151.11,151.1,151,92,150.5 340/147,150,147MT,172.5,146.1 328/26 307/261 318/562
• US Class Current: 700/9
• CPC Class Codes: G05B 19/4063 Monitoring general control system G05B19/4062 takes precedence
• CPC Class Codes: G05B 19/4181 characterised by direct numerical control [DNC]
• CPC Class Codes: G08B 26/00 Alarm systems in which substations are interrogated in succession by a central station
• CPC Class Codes: Y02P 90/02 Total factory control, e.g. smart factories, flexible manufacturing systems [FMS] or integrated manufacturing systems [IMS]

Abstract

The multiplexing circuit disclosed includes a translator and a plurality of separate interface circuits adapted to be alternatively connected to the translator over a single buss. Each of the interface circuits is connected to a plurality of specific points at which electrical conditions are to be monitored in a corresponding one of a plurality of machine tool control panels. Monitoring of all the control panels is accomplished in conjunction with one translator multiplexed to the separate interface circuits under sequencing control of a computer connected to the translator and interface panels. The translator converts the usual 115-volt alternating current signals from the control circuits into signals usable by the computer. In operation the computer at a desired speed and in a desired sequence will provide control signals to the separate interface circuits to connect the control panels of individual machine tools to the translator for translation of monitored signals to the computer. Thus each of a plurality of separate machine tools is monitored with a single computer without the necessity of separate conversion circuits at each control panel. Only the standard 115-volt 60-cycle alternating current electric energy of the control panels pass between the interface panels and the translator.

Claims

1. A computer multiplexing system for monitoring a plurality of electrical control panels comprising a translator for transmitting signals passed thereto in a form unsuitable for use by a computer to a computer in a usable form, a plurality of interface circuits one connected to each of the individual control panels for monitoring a plurality of different conditions in each control panel and a single buss connected between the translator and individual interface circuits for passing signals in a form unusable by the computer between the interface circuits and the translator and means within the interface circuits responsive to computer commands for selectively isolating all but one of the interface circuits from the buss and translator.

2. Structure as set forth in claim 1, wherein the control panels are 115-volt, 60-cycle alternating current energized and the buss is energized directly from the control panels.

3. Structure as set forth in claim 2, wherein the translator includes a separate relay coil for each of the plurality of conditions to be monitored in the control panels and isolated relay contacts operably associated with each separate relay coil each connected in a separate computer circuit.

4. A multiplexing circuit for monitoring electrical control panels of a plurality of machine tools with a single computer, comprising a translator for simultaneously receiving a plurality of electrical signals representative of a plurality of separate conditions in a single control panel for actuating the computer in accordance therewith, means for returning the signals to the control panels from the translator and means connected between the control panels and translator for selectively coupling the control panels to the translator and for selectively isolating the control panels from the translatOr under control of the computer.

5. A multiplexing circuit for monitoring electrical control panels of a plurality of machine tools with a single computer, comprising a translator for simultaneously receiving a plurality of electrical signals representative of a plurality of separate conditions in a single control panel for actuating the computer in accordance therewith, means for returning the signals to the control panels from the translator and means connected between the control panels and translator for selectively coupling the control panels to the translator and for selectively isolating the control panels from the translator under control of the computer including a separate solenoid coil actuated by the computer for each control panel, normally open relay contacts in a single return line from the translator to the control panels and in a separate conductor from each control circuit for each condition monitored, each of which are in series with an isolating diode.

6. A multiplexing circuit for monitoring electrical control panels of a plurality of machine tools with a single computer, comprising a translator for simultaneously receiving a plurality of electrical signals representative of a plurality of separate conditions in a single control panel for actuating the computer in accordance therewith, means for returning the signals to the control panels from the translator and means connected between the control panels and translator for selectively coupling the control panels to the translator and for selectively isolating the control panels from the translator under control of the computer including a pair of isolating diodes, a first path to the translator through a dropping resistor, and a first return path through a normally open relay contact under control of the computer, and a second return path having no resistance therein, including an isolating diode and normally closed relay contacts under control of the computer.

7. A computer multiplexing system for monitoring a plurality of electrical control panels comprising a translator for transmitting signals passed thereto in a form unsuitable for use by a computer to a computer in a usable form, a plurality of interface circuits one connected to each of the individual control panels for monitoring a plurality of different conditions in each control panel and a single buss connected between the translator and individual interface circuits for passing signals in a form unusable by the computer between the interface circuits and the translator and means operably connected to the interface circuits responsive to computer commands for selectively isolating all but one of the interface circuits from the buss and translator.

8. The method of multiplexing for monitoring machine tools or the like comprising sensing a plurality of electrical signals representative of a plurality of separate conditions in a plurality of separate machine tool control panels which signals are in a form unusable by a computer, passing the electrical signals over a single buss to a translator for translating the signals into signals usable by a computer, translating the sensed signals into signals usable by a computer, and selectively coupling the control panels to the translator in response to signals from the computer.

9. The method as set forth in claim 8 wherein selectively coupling the control panels to the translator includes selectively passing the signals from control panels it is desired not to connect to the computer around the single buss and translator.

10. The method as set forth in claim 8 wherein selectively coupling the control panels to the translator includes isolating control panels it is desired not to connect to the computer from the translator.