Convenient Testing And Diagnostic Options - Siemens SIMATIC S7-400 Configuration And Use Manual

7.3

Convenient Testing and Diagnostic Options

Testing Functions
SIMATIC S7 provides convenient testing functions for testing the user program.
You can monitor both the block status and the variable status.
The test functions allow you to perform quick commissioning and easily locate
errors.
Information Functions
High-performance information functions are provided in addition to the testing
functions. The CPUs provide information about:
• Type and version of the CPU
• Their "performance specifications"
(e.g. type and number of operands)
• Available and used memory capacity
• Current status of the automation system
(e.g. module(s) "Ok", configuration of the automation system, error events
that have occurred, chronology of the events).
Diagnostics in the User Program
You can include blocks for error handling in the user program with STEP 7.
Example: Organization blocks (OBs) for handling programming and device errors,
for example, for calling unloaded blocks, for unacknowledged modules or for
battery failure.
Not only CPUs can trigger an OB call, diagnostic-capable modules can also do
this. These modules generate a diagnostic interrupt that results in the call of an
error OB. The error OBs provide detailed information about the type, location and
time of the error.
Diagnostics with PG or OP
What must you do to have diagnostic data displayed by the display system such as
a programming device or operator panel? The answer in the easiest case is
nothing! For example, when the CPU is set to STOP by an error, it automatically
sends the most recent diagnostic message to the connected display system,
providing you with immediate feedback about what is happening in the automation
system.
Every diagnostic event, even one that does not result in a CPU STOP, can be
evaluated with the connected display system. Several options are available for an
evaluation:
• Evaluation of the current status of the automation system
• Evaluation of the "history" of diagnostic events
Automation System S7-400 Configuration and Use
A5E00442711-02
Programming the S7-400
7-5