Programmable controller

Abstract

A programmable controller has a multi-purpose processor such as an MPU and an application specific control device such as an ASIC (application specific integrated circuit). When the MPU requests the ASIC to execute a user program and the ASIC is activated, the MPU executes an event process while the ASIC executes the requested user program. When the MPU requests the ASIC to execute a DMA transfer process in an input/output refresh process and the ASIC is activated, the MPU executes an event process while the ASIC executes the requested DMA transfer process.

1 . A programmable controller comprising: 
 an I/O unit connected to controlled apparatus; and    a CPU unit including a multi-purpose processor and an application specific control device and serving to execute cyclically a series of processes including execution of a user program, an I/O refresh and an event process;    wherein the execution of said I/O refresh includes receiving input data of said controlled apparatus from said I/O unit and transmitting results of execution of said user program as output data to said I/O unit;    wherein the execution of said user program includes using said input data received from said I/O unit in logical formula in said user program;    wherein the execution of said event process is carried out for peripheral components;    wherein said multi-purpose processor carries out a common process when said programmable controller is started, thereafter makes a request to said application specific control device to execute said user program and activates said application specific control device and thereafter executes said event process concurrently as said application specific control device executes said user program;    wherein said application specific control device serves to sequentially take in commands in said user program as said request is received, to judge whether said commands can be executed by said application specific control device, to execute those of said commands judged to be executable and to request said multi-purpose processor to execute those of said commands judged not to be executable by said application specific control device; and    wherein said multi-purpose processor serves to execute those of said commands judged not to be executable by said application specific control device, if requested by said application specific control device, after terminating execution of said event process.    
   
   
       2 . The programmable controller of  claim 1  wherein said multi-purpose processor is a software processor and said application specific control device comprises a hardware circuit.  
   
   
       3 . The programmable controller of  claim 1  wherein said multi-purpose processor activates said application specific control device when said user program is found to contain a command which is executable more quickly by said application specific control device.  
   
   
       4 . The programmable controller of  claim 1  wherein said application specific control device serves to output an interrupt signal when a command not executable thereby is encountered in said user program and said multi-purpose processor, when said interrupt signal is received, serves to interrupt said event process and to execute said command.  
   
   
       5 . The programmable controller of  claim 1  further comprising an I/O unit for specifying a normal mode and a parallel execution mode, said normal mode being a mode of operation wherein said user program and said event process are not carried out in parallel and said parallel execution mode is another mode of operation wherein said user program and said event process are carried out in parallel.  
   
   
       6 . A method of controlling a programmable controller that comprises an I/O unit connected to controlled apparatus and a CPU unit that includes a multi-purpose processor and an application specific control device, said method comprising the steps of 
 causing said programmable controller to execute cyclically a series of processes including execution of a user program, an I/O refresh process and an event process, wherein the execution of said I/O refresh includes receiving input data of said controlled apparatus from said I/O unit and transmitting results of execution of said user program as output data to said I/O unit, wherein the execution of said user program includes using said input data received from said I/O unit in logical formula in said user program, and wherein the execution of said event process is carried out for peripheral components; and    designing said multi-purpose processor and said application specific control device such that said multi-purpose processor, when said multi-purpose processor requests said application specific control device to execute said user program and activates said application specific control device, executes said event process concurrently as said application specific control device executes said user program.