Machine operating condition monitoring system

Abstract

This invention relates to a system for monitoring the condition and operation of remotely located machines, such as coin-operated vending machines. In one embodiment, switches in each machine convert operating conditions into a binary digital word for that machine, which is stored temporarily. Such words for a plurality of machines are then transferred to a memory, whence they are retrieved, coded as to machine number and transmitted via telephone line to a control processing unit where the various machine conditions are recorded and displayed.

What is claimed is: 
     
       1. A system for monitoring a plurality of machines having widely spaced locations comprising: a plurality of .[.binary.]. sensors connected to each machine;   a plurality of local data storage and processing units, each corresponding to a separate group of machines and connected to every machine in that group;   means to sequentially feed .[.binary.]. information from sensors in each machine of a group to said local data storage and processing unit corresponding to that group;   comparison means in said local data storage and processing unit for comparing received sensor information with previous information received from the same sensor and determining and indicating the existence of a change;   a central processing unit;   scanning means for scanning said local data storage and processing units and .Iadd.selectively .Iaddend.retrieving from them .[.only.]. changed information; and   transmission means for transmitting said changed information to said central processing unit.   
     
     
       2. The system of claim 1 wherein further: said .[.binary.]. sensors comprise sensors connected to indicate at least one machine operation;   said local data storage and processing units each contain operation count means connected to said comparison means for counting the number of operations of said at least one machine operation and operation storage means for storing the result of said operation count means; and   said scanning means retrieves from each said local data storage and processing unit any changed operation count information.   
     
     
       3. The system of claim 1 wherein further: said .[.binary.]. sensors comprise sensors connected to indicate the existence of at least one machine condition requiring attention; and   said central processing unit contains indicating means responsive to the existence of changed machine condition information for providing an indication that a machine needs attention.   
     
     
       4. The system of claim 1 wherein further: said .[.binary.]. sensors comprise sensors connected to indicate at least one machine operation and to indicate the existence of at least one machine condition requiring attention;   said local data storage and processing units each contain operation count means connected to said comparison means for counting the number of operations of said at least one machine operation and operation count storage means for storing the result of said operation count means;   said scanning means retrieves any changed operation count information from each said local data storage and processing unit; and   said central processing unit contains indicating means responsive to the existence of changed machine condition information for providing an indication that a machine needs attention.   
     
     
       5. The system of claim 1 wherein: said means to sequentially feed .[.binary.]. information from sensors in each machine to a local data storage and processing unit includes   a. shift register storage means associated with each machine for storing information from each said sensor connected to that machine; and   b. means associated with each said local storage and processing unit for sequentially feeding information from all associated machine shift register storage means to said local data storage and processing unit.   
     
     
       6. The system of claim 1 wherein at periodic intervals all of the information stored in said local data storage and processing units, whether recently changed or not, is transmitted to said central processing unit. 
     
     
       7. The system of claim 1, including further origin identification means for adding to said information selected for transmission via said transmission means an identification of the location from which said information was obtained.