Extended instructions
9.3 Distributed I/O (PROFINET, PROFIBUS, or AS-i)
S7-1200 Programmable controller
System Manual, V4.2, 09/2016, A5E02486680-AK
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From a machine OEM's point of view, there are numerous device options possible in series
production of machines. However, each delivered machine includes only one combination of
selected options.
The manufacturer configures every one of these possible machine options as a PROFINET
IO device. The manufacturer does this in order to create and maintain a common user
program having all possible options. Use D_ACT_DP to deactivate all PROFINET IO devices
not present at machine startup.
A similar situation exists for machine tools having numerous tooling options available, but
actually using only a few of them at any given time. These tools are implemented as
PROFINET IO devices. With D_ACT_DP, the user program activates the tools currently
needed and deactivates those required later.
If you have started a deactivation or activation job and you call D_ACT_DP again before the
job is complete, the behavior of the instruction depends on whether or not the new call
involves the same job. If the input parameter LADDR matches, the call is interpreted as a
follow-on call.
Deactivating PROFINET IO devices
When you deactivate a PROFINET IO device with D_ACT_DP, its process outputs are set to
the configured substitute values or to "0" (safe state). The assigned PROFINET IO controller
does not continue to address this component. The error LEDs on the PROFINET IO
controller or CPU do not identify the deactivated PROFINET IO devices as faulty or missing.
The CPU updates the process image inputs of deactivated PROFINET IO devices with "0".
Therefore, the CPU treats the deactivated PROFINET IO devices just like failed PROFINET
IO devices.
If you directly access the user data of a previously deactivated PROFINET IO device from
your program, the system behavior depends on the block’s error handling selection:
● If global error handling is enabled, the system enters an access error start event into the
diagnostic buffer and stays in RUN.
● If block-local error handling is enabled, the system enters an error cause in the error
structure. You can access the error cause using the GET_ERROR_ID (Page 311)
instruction.
An error for a read access returns "0". Refer to "Event execution priorities and queuing"
(Page 105) for further information on error handling.
If you attempt to access a deactivated PROFINET IO device using an instruction (such as
"RD_REC (Page 385)"), you receive the same error information in RET_VAL as for an
unavailable PROFINET IO device.
If a PROFINET IO station fails after you have deactivated it with D_ACT_DP, the operating
system does not detect the failure.
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