Omron CJ1W-PNT21 Operation Manual page 112

Configuring the IO Controller
Note
!Caution
Auto Addressing
!Caution
Note
Example
98
1 The end address of each Input/Output area in the PLC memory,
depends on the size of the allocated I/O data.
2 If more than 100 words of input or output have been configured for
the slave, overlap of memory areas will occur in the PLC, if default
I/O mapping is used as shown above.
The default mapping of areas on to the PLC memory is the same default mapping as
used in the CJ1W-DRM21 Devicenet Master/Slave Unit and the CJ1W-PRM21
PROFIBUS Master. Care should be taken to avoid data overlap, if such a Unit is part of
the same PLC CPU system as the CJ1W-PNT21 PROFINET IO Controller Unit.
The CJ1W-PNT21 PROFINET IO Controller Unit, will assemble the correct
PROFINET data messages from the storage order in the Input and Output
memory areas.
The default allocation of I/O modules, i.e. I/O modules are mapped in
ascending order of IO Device No. and module selection, uses the concept of
Auto Addressing of the CJ1W-PNT21 IO Controller DTM. Auto Addressing will
(re)allocate I/O modules according to the algorithm explained above in each
area.
If a configuration has been selected, which is changed later - for example - by
adding an I/O module to one of the IO Devices, the Auto Addressing feature
will add that module to the default area, between the already selected
modules of that particular slave device.
When an I/O module is added to or deleted from a configuration at a later point in time,
Auto Addressing will cause a change in the addresses of subsequent I/O modules in an
Input/Output area. This will cause I/O data of (a part of the) IO Devices to be re-mapped
to different locations in the PLC memory. In order to avoid unexpected results, the PLC
user program may have to be adapted as well.
1 Auto Addressing will not change the allocation of I/O modules to a
certain area, i.e. a module allocated to Input/Output area 2, will not
be re-allocated to area 1, if Auto Addressing is enabled
2 Auto Addressing will not change the start address of the areas.
3 Auto Addressing is by default enabled, when starting a new project. It
is however, disabled for existing projects to avoid unwanted re-map-
ping.
The figure below shows an example of the effects of Auto Addressing on
(re)allocation of I/O modules. In the original I/O configuration on the left, the
first slave - an OMRON GRT1-PNT - consisted of one Output modules. In new
configuration one I/O module was inserted, and subsequent modules were re-
allocated in the process
Section 7-4