| 摘要 |
An intelligent programmable process control system is responsive to the states of sensors located along a process for controlling the states of controllable devices located along the process. The system includes a microprocessor which sequentially scans an addressable memory to execute a sequence of boolean logic instructions in accordance with the states of the sensors to control the controllable devices accordingly. The microprocessor includes means for generating an end-of-scan signal upon execution of the last instruction of a sequence contained in memory. Receptor means is provided for receiving extended addressable memory for storing additional instructions of the sequence if required, the receptor means including indicator signal generator means for generating a signal indicative of the presence of such extended memory in the receptor means. An end-of-scan generator means, coupled to the indicator signal generator means, automatically generates an end-of-scan signal whenever the extended memory means is addressed by the microprocessor means and the indicator signal generator indicates that the receptor does not contain extended memory. The end-of-scan signals provided by the microprocessor and the end-of-scan signal generator are utilized to control the microprocessor to begin rescanning the addressable memory, as well as, controlling the transfer of data to a communications register which communicates with the sensors and controllable devices.
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