Programming options
5.4 Other features to make programming easy
Easy Book
68
Manual, 05/2009, A5E02486774-01
The clock memory byte cycles the
individual bits on and off at fixed intervals.
The clock flags each generate a square
wave pulse on the corresponding M
memory bit. These bits can be used as
control bits, especially when combined with
edge instructions, to trigger actions in the
user code on a cyclic basis.
5.4.2
Watch tables make monitoring the user program easy
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, bit memory (M), and data blocks (DB). (Page 33) With a watch table, you
can enable the peripheral 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.
A watch table also allows you to "force" or set a tag to a specific value. (Page 95) Forced
values are applied once per scan. They can be changed during program execution but for
outputs, the forced values will be written at the end of the scan. To force a tag or memory
address, simply click the one of the "Force" buttons.
