Technical data

Contents
Programming with STEP 7
Manual, 05/2010, A5E02789666-01 19
20.4.3 Inserting Modify Values ........................................................................................................449
20.4.4 Upper Limits for Entering Timers..........................................................................................450
20.4.5 Upper Limits for Entering Counters ......................................................................................451
20.4.6 Inserting Comment Lines......................................................................................................451
20.4.7 Examples ..............................................................................................................................452
20.4.7.1 Example of Entering Addresses in Variable Tables .............................................................452
20.4.7.2 Example of Entering a Contiguous Address Range .............................................................453
20.4.7.3 Examples of Entering Modify and Force Values...................................................................454
20.5 Establishing a Connection to the CPU..................................................................................456
20.6 Monitoring Variables .............................................................................................................457
20.6.1
Introduction to Monitoring Variables .....................................................................................457
20.6.2 Defining the Trigger for Monitoring Variables.......................................................................457
20.7 Modifying Variables...............................................................................................................459
20.7.1 Introduction to Modifying Variables.......................................................................................459
20.7.2 Defining the Trigger for Modifying Variables ........................................................................460
20.8 Forcing Variables..................................................................................................................462
20.8.1 Safety Measures When Forcing Variables ...........................................................................462
20.8.2 Introduction to Forcing Variables..........................................................................................463
20.8.3 Differences Between Forcing and Modifying Variables........................................................465
21 Testing Using Program Status...............................................................................................................467
21.1 Program Status Display ........................................................................................................468
21.2 What You Should Know About Testing in Single-Step Mode/Breakpoints...........................470
21.3 What You Should Know About the HOLD Mode ..................................................................472
21.4 Program Status of Data Blocks.............................................................................................473
21.4.1
Setting the Display for Program Status.................................................................................474
22 Testing using the Simulation Program (Optional Package) ...............................................................475
22.1 Testing using the Simulation Program S7 PLCSIM (Optional Package)..............................475
23 Diagnostics ..............................................................................................................................................477
23.1 Hardware Diagnostics and Troubleshooting.........................................................................477
23.2 Diagnostics Symbols in the Online View ..............................................................................479
23.3 Diagnosing Hardware: Quick View .......................................................................................481
23.3.1
Calling the Quick View..........................................................................................................481
23.3.2 Information Functions in the Quick View ..............................................................................481
23.4 Diagnosing Hardware: Diagnostic View ...............................................................................482
23.4.1 Calling the Diagnostic View ..................................................................................................482
23.4.2 Information Functions in the Diagnostic View.......................................................................484
23.5 Module Information ...............................................................................................................485
23.5.1 Options for Displaying the Module Information.....................................................................485
23.5.2 Module Information Functions ..............................................................................................486
23.5.3 Scope of the Module Type-Dependent Information..............................................................488
23.5.4 Displaying the Module Status of PA Field Devices and DP Slaves After a Y-Link...............490
23.6 Diagnosing in STOP Mode ...................................................................................................492
23.6.1 Basic Procedure for Determining the Cause of a STOP ......................................................492
23.6.2 Stack Contents in STOP Mode.............................................................................................493
23.7 Checking Scan Cycle Times to Avoid Time Errors...............................................................494
23.7.1 Checking Scan Cycle Times to Avoid Time Errors...............................................................494
23.8 Flow of Diagnostic Information .............................................................................................495
23.8.1 System Status List SSL ........................................................................................................496
23.8.2 Sending Your Own Diagnostic Messages ............................................................................499
23.8.3 Diagnostic Functions.............................................................................................................500
23.9 Program Measures for Handling Errors................................................................................501