107BOnline and diagnostic tools
14.10 Monitoring and modifying values in the CPU
S7-1200 Programmable controller
System Manual, 11/2011, A5E02486680-05
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14.10.4.2
Enabling outputs in STOP mode
The watch table allows you to write to the outputs when the CPU is in STOP mode. This
functionality allows you to check the wiring of the outputs and verify that the wire connected
to an output pin initiates a high or low signal to the terminal of the process device to which it
is connected.
WARNING
Even though the CPU is in STOP mode, enabling a physical output can activate the
process point to which it is connected.
You can change the state of the outputs in STOP mode when the outputs are enabled. If the
outputs are disabled, you cannot modify the outputs in STOP mode.
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To enable the modification of the outputs in STOP, select the "Enable peripheral outputs"
option of the "Modify" command of the "Online" menu, or by right-clicking the row of the
Watch table.
You cannot enable outputs in STOP mode if you have configured distributed I/O,. An
error is returned when you try to do this.
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Setting the CPU to RUN mode disables "Enable peripheral outputs" option.
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If any inputs or outputs are forced, the CPU is not allowed to enable outputs while in
STOP mode. The force function must first be cancelled.
14.10.5
Forcing values in the CPU
14.10.5.1
Using the force table
A force table provides a "force" function that overwrites the value for an input or output point
to a specified value for the peripheral input or peripheral output address. The CPU applies
this forced value to the input process image prior to the execution of the user program and to
the output process image before the outputs are written to the modules.
Note
The force values are stored in the CPU and not in the force table.
You cannot force an input (or "I" address) or an output (or "Q" address). However, you can
force a peripheral input or peripheral output. The force table automatically appends a ":P" to
the address (for example: "On":P or "Run":P).