Technical data

Table Of Contents
Organization Blocks
System Software for S7-300/400 System and Standard Functions - Volume 1/2
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A5E00709327-01
1.19 Insert / Remove Module Interrupt Organization Block
(OB83)
Description
The CPU operating system calls OB 83 in following situations:
after insertion / removal of a configured module
after modifications of module parameters under STEP 7 and download of
changes to the CPU during RUN
You can disable/delay/enable the insert/remove interrupt OB with the help of SFCs
39 to 42.
Module insertion and removal
Each time a configured module is removed or inserted during the RUN, STOP, and
STARTUP modes, an insert/remove interrupt is generated (power supply modules,
CPUs, adapter modules and IMs must not be removed in these modes). This
interrupt causes an entry in the diagnostic buffer and in the system status list for
the CPU involved. The insert/remove OB is also started if the CPU is in the RUN
mode. If this OB has not been programmed, the CPU changes to the STOP mode.
Then system polls S7-400 modules in seconds intervals to detect insertion or
removal. To enable the CPU to detect the removal and insertion of an S7-400
module, a minimum time interval of two seconds must expire between removal and
insertion. This minimum time is slightly higher for other modules.
If you remove a configured module in the RUN mode, OB83 is started. Since the
existence of modules is only monitored at intervals of one second, an access error
may be detected first if the module is accessed directly or when the process image
is updated.
If you insert a module in a configured slot in the RUN mode, the operating system
checks whether the type of the module inserted corresponds to the recorded
configuration. OB83 is then started and parameters are assigned if the module
types match.
Special considerations for S7-300
Central IO devices cannot be inserted and removed with S7-300.
With respect to distributed IO devices, CPU 318 behaves like an S7-400-CPU.
With all other S7-300 CPUs, there is an insert/remove interrupt only for 31x
PN/DP CPUs, but then only for PROFINET IO components.
With IM151/CPU (CPU with ET 200S), there is an insert/remove interrupt only
for central IO devices.