Operation Cycle of PLC

Operation Cycle :- 

             The operation will occur after the successful downloading of our program into the PLC and in this we will define all the different process performed by the controller.

It includes

(i)                 Input Scan

(ii)               Program Scan

(iii)             Output Scan

(iv)             Communication Services

(v)               House Keeping  

(I)               INPUT SCAN:-  

            In this process our controller will read the data and checks the types of input that have been used in any process the time required for this process will be in micro seconds.

(II)           PROGRAM SCAN:-

              In this process our controller will checks the logics and  instructions that have been used. The time required for this operation depends upon the number of instructions used in any program.

(III)        OUTPUT SCAN:- 

           In this process our controller will writes the data that will considered as an output. The time required for this process will also be in micro seconds.

(IV)        COMMUNICATION SERVICES:-

           In this process our controller checks the communication with other devices i.e. Laptop/PC.

NOTE:-   In Micrologix 1000, we have

Internal timers=40

External counters=32

 If more internal timer or counter have been than there will be an error.