99BProgramming concepts
6.9 Debugging and testing the program
S7-1200 Programmable controller
System Manual, 11/2011, A5E02486680-05
159
6.9
Debugging and testing the program
6.9.1
Monitor and modify data in the CPU
As shown in the following table, you can monitor and modify values in the online CPU.
Table 6- 5
Monitoring and modifying data with STEP 7
Editor
Monitor
Modify
Force
Watch table
Yes
Yes
No
Force table
Yes
No
Yes
Program editor
Yes
Yes
No
Tag table
Yes
No
No
DB editor
Yes
No
No
Monitoring with a
watch table
Monitoring with the LAD editor
Refer to the "Online and diagnostics" chapter for more information about monitoring and
modifying data in the CPU (Page 642).
6.9.2
Watch tables and force tables
You use "watch tables" for monitoring and modifying the values of a user program being
executed by the online CPU. You can create and save different watch tables in your project
to support a variety of test environments. This allows you to reproduce tests during
commissioning or for service and maintenance purposes.
With a watch table, you can monitor and interact with the CPU as it executes the user
program. You can display or change values not only for the tags of the code blocks and data
blocks, but also for the memory areas of the CPU, including the inputs and outputs (I and Q),
peripheral inputs (I:P), bit memory (M), and data blocks (DB).
With the watch table, you can enable the physical outputs (Q:P) of a CPU in STOP mode.
For example, you can assign specific values to the outputs when testing the wiring for the
CPU.
