| 摘要 |
<p>A microprocessor based sequence controller is disclosed in connection with a soup and beverage vending machine, in which sequences of functions required in the operation of the vending machine are under the control of the microprocessor unit. The microprocessor unit has two separate storage sections, one of which is not alterable and contains the basic program for the vending machine. The other section is alterable and contains adjustable modifications of the basic program. The alterable storage section is modifiable through the use of a separate service module, which is not normally connected with the sequence controller during normal vending operations. In this way, the integrity of the program modifications is assured. The service module is small and inexpensive, includes a minimum number of components, and is readily attachable and detachable from the sequence controller. The start and stop times of each function of the sequence of functions are independently modifiable, and an interlock is provided to assure against unintentional modification of the start and stop times. In operation, one of a plurality of sequences is selected and the microprocessor starts a sequence of functions by energizing a continuously running timer, the state (or time) of which is continuously compared with each of the stored start and stop times, each of such times being calculated by adding the modification, if any, to the appropriate value of the basic program. When a coincidence is found, a relevance test is executed, so that coincidences which are not relevant to a selected sequence are ignored. The integrity of the stored modifications is automatically checked periodically, and the stored modifications are ignored if the integrity check fails.</p> |
