Ladder Viewer And Ladder Add-On (828D Only); Plc Diagnostics - Siemens SINUMERIK 840D SL Operating Manual

Ladder Viewer and Ladder add-on (828D only)

21.1

PLC diagnostics

A PLC user program consists to a large degree of logical operations to implement safety
functions and to support process sequences. These logical operations include the linking of
various contacts and relays. These logic operations are displayed in a ladder diagram.
Ladder add-on tool
As 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 causes
or program errors.
Editing of interrupt routines
You 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 data
Using the Ladder add-on tool, you can "re-wire" inputs (via INT_100) or outputs (via
INT_101) for service purposes.
Generating INT_100 / INT_101 block
If one or several INT_100 or INT_101 blocks are missing, they can be added via the vertical
softkey bar. If these INT blocks exist in a project, they can be deleted via the vertical softkey
bar. You also have the opportunity to change the networks of a program on the control as
well as to save and load these changes.
Note
Saving the PLC project when changing the operating area
If you have created INT_100/INT_101 blocks or inserted, removed or edited networks in an
INT block, you must save the project before you change from the PLC area into another
operating area. Transfer the project into the PLC using the "Download to CPU" softkey. If
this is not done, all of the changes will be lost and must be re-entered.
Milling
Operating Manual, 02/2012, 6FC5398-7CP40-3BA0
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