Sunday, August 7, 2011

The Translation Tool of PLC 5 and SLC 500 Processor

A Logix controller maintains one constant task that runs in a mode of self-triggered. It regenerates itself after each end. The permanent task runs as the task of lowest priority in the controller. This indicates that all periodic jobs will interrupt the permanent task. The conversion tool automatically makes one continuous task named Continuous with a watchdog default setting of 500 msec. This job is the main job of the converted project.

The tool of translation makes a main routine named mcpMain, which registers one or more routines within this continuous task. This major routine contains the instructions of JSR to each other routines.
• In the processors of PLC-5, the first MCP (master control program) turns into the main routine. The tool of translation uses the status file of PLC-5 to decide which the first MCP is.
• In the processors of SLC 500, ladder program 2, this is the key ladder program, to be the main routine.
Each staying routine within a program is measured a subroutine. Subroutines are local in the program scope. As a result of this, it is probable for ladder programs to come out as the same subroutine in multiple programs. The translation process does not describe a fault routine for a program. You must identify the fault routine yourself, if required.

STIs (Converting Selectable Timed Interrupts)
The status of processor word 31 includes the ladder program number, if any, that is selected for use as a STI (selectable timed interrupt). The tool of translation translates this program file into the periodic task main routine named STI. The tool of translation recovers the interval of STI from the status file of processor. It translates the interval to a 1 msec time base. You will have to correct the properties of task to identify its priority after the conversion. The status of processor bit S:2/1 permits the STI enabling and disabling. The tool of translation produces an instruction PCE if it meets any references to S:2/1.

DIIs/PIIs (Converting Input Interrupts)
A Logix controller does not support DIIs or PIIs input interrupts. If the processor of PLC-5 has a PII or the processor of SLC 500 has a DII, the tool of translation translates it to a routine in the Continuous task. You have to edit the Logix logic to identify the routine of converted. The status of processor word 46 recognizes the file of program to be used as a PII or DII. The tool of translation creates an instruction of PCE and places it in the translated DII/PII routine.


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