9. easyE4 inside9.1 Program execution9. easyE4 inside9.1 Program executionWhen using the LD or FBD programming language, the program will be executed as fol-lows:l The program will start by reading the hardware's input states and writing them tothe image table register. After this, it will run through network 01 in its entirety andnot only process all function blocks and logic circuitry, but also write the state of allmapping assignments (Q, M, etc., and function blocks) to the image table register. Itwill then run through the next network (if any networks are jumped over, they willnot be run through). Once the last network has been run through, the resulting out-put states will be transmitted to the hardware and the cycle will start again.In the Programming language STl The program will start by reading the hardware's input states and writing them tothe image table register. After this, it will execute the statement and instruction listfrom top to bottom and modify the image table register every time there is a map-ping assignment (if any statements or instructions are jumped over, they will not beexecuted). The cycle will then start again.When using the EDP (easy Device Programming) programming languagel This programming language is the same one that can be use for programming dir-ectly on the base device. The way in which this program will be executed isidentical to the way programs are executed on the easy500, easy700, and easy800devices.In conventional control systems, a relay or contactor control processes all the rungs inparallel. The speed with which a contactor switches is thus dependent on the com-ponents used, and ranges from 15 to 40 ms for relay pick-up and drop-out.ReadprocessimageProcess circuitdiagram and func-tionblock diagramWriteprocessimageLocalinputsLocaloutputsFunctionblockinputsFunctionblockoutputsMarkers MarkersDiagnosticsinformationNET sta-tions out-Table 87: Cycle timeeasyE4easyE4 11/18 MN050009 EN www.eaton.com 501
