MillingOperating Manual, 02/2012, 6FC5398-7CP40-3BA0 655Ladder Viewer and Ladder add-on (828D only) 2121.1 PLC diagnosticsA PLC user program consists to a large degree of logical operations to implement safetyfunctions and to support process sequences. These logical operations include the linking ofvarious contacts and relays. These logic operations are displayed in a ladder diagram.Ladder add-on toolAs a rule, the failure of a single contact or relay results in a failure of the whole system.Using the Ladder add-on tool, you can perform a PLC diagnosis in order to find fault causesor program errors.Editing of interrupt routinesYou can edit the following interrupt programs:● INT_100 - interrupt program, (is executed before the main program)● INT_101 - interrupt program, (is executed after the main program)Marshalling dataUsing the Ladder add-on tool, you can "re-wire" inputs (via INT_100) or outputs (viaINT_101) for service purposes.Generating INT_100 / INT_101 blockIf one or several INT_100 or INT_101 blocks are missing, they can be added via the verticalsoftkey bar. If these INT blocks exist in a project, they can be deleted via the vertical softkeybar. You also have the opportunity to change the networks of a program on the control aswell as to save and load these changes.NoteSaving the PLC project when changing the operating areaIf you have created INT_100/INT_101 blocks or inserted, removed or edited networks in anINT block, you must save the project before you change from the PLC area into anotheroperating area. Transfer the project into the PLC using the "Download to CPU" softkey. Ifthis is not done, all of the changes will be lost and must be re-entered.
