Easy To Monitor And Test Your User Program; Watch Tables And Force Tables - Siemens SIMATIC S7-1200 Manual

Programming made easy

6.5 Easy to monitor and test your user program

Table 6- 23 DataLogOpen and DataLogClose instructions
LAD/FBD SCL
"DataLogOpen_DB"(
"DataLogClose_DB"(
6.5 Easy to monitor and test your user program
6.5.1

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.
STEP 7 also provides a force table for "forcing" a tag to a specific value. For more
information about forcing, see the section on forcing values in the CPU (Page 261) in the
"Online and Diagnostics" chapter.
Note
The force values are stored in the CPU and not in the watch table.
You cannot force an input (or "I" address). However, you can force a peripheral input. To
force a peripheral input, append a ":P" to the address (for example: "On:P").
114
req:=_bool_in_,
mode:=_uint_in_,
done=>_bool_out_,
busy=>_bool_out_,
error=>_bool_out_,
status=>_word_out_,
name:=_string_inout_,
ID:=_dword_inout_);
req:=_bool_in_,
done=>_bool_out_,
busy=>_bool_out_,
error=>_bool_out_,
status=>_word_out_,
ID:=_dword_inout_);
Description
The DataLogOpen instruction opens a pre-existing data log
file. A data log must be opened before you can write new
records to the log. Data logs can be opened and closed
individually. Eight data logs can be open at the same time.
The DataLogClose instruction closes an open data log file.
DataLogWrite operations to a closed data log result in an error.
No write operations are allowed to this data log until another
DataLogOpen operation is performed.
A transition to STOP mode closes all open data log files.
Easy Book
Manual, 03/2014, A5E02486774-AF