Programmable controller which allows for removal of the I/O modules during an on-line mode
AssigneeMitsubishi Denki Kabushiki Kaisha
InventorsTatsumi Yabusaki, Toshimitsu Asai
Life of this patent
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Abstract
A programmable controller that allows input and output modules to be changed during an on-line mode with minimal interaction by the user. The controller includes a request table that separately stores change request signals generated by each module. In a first embodiment, the controller periodically polls this request table to determine whether any module has issued a change request. The controller disables each module that issues a change request. When a new module is loaded, the controller enables this module once the corresponding change request signal is removed from the request table. In a second embodiment, the controller uses an interrupt circuit to interrupt processing when a change request is initiated.
Claims15
A programmable controller for controlling peripheral devices comprising:
- a CPU module for controlling operation of the peripheral devices while in an on-line mode according to a sequence program stored therein, said CPU module repeatedly performing end processing while performing sequence processing based on said sequence program;
- an input module, connected between the CPU module and a first peripheral device, for inputting information signals from the first peripheral device to said CPU module;
- and
- an output module, connected between the CPU module and a second peripheral device, for outputting control signals from said CPU module to said second peripheral device,
- at least one of said input and output modules including a change requesting device for outputting a module change request signal to said CPU module during an on-line mode thereof,
- said CPU module comprising:
- a change request data table means for receiving and storing said module change request signals as request data, and
- change processing means for automatically placing one of said input and output modules in a changeable state in response to said request signals.
A programmable controller for controlling peripheral devices comprising:
- a CPU module for controlling operation of said peripheral devices while in an on-line mode based on a sequence program, said CPU module performing end processing in response to an interrupt signal;
- an input module, connected between the CPU module and a first peripheral device, for inputting information signals from the first peripheral device to said CPU module;
- and
- an output module, connected between the CPU and a second peripheral device, for outputting control signals from said CPU module to said second peripheral device,
- at least one of said input and output modules including change requesting means for outputting a module change request signal to said CPU module during an on-line mode,
- said CPU module comprising:
- interrupt signal detecting means for detecting the module change request signal and for generating said interrupt signal in response thereto, and
- change processing means for automatically performing end processing, in order to place one of said input and output modules in a changeable state in response to said interrupt signal.
Dependencies are inferred from the claim text.