Omron CJ1W-PNT21 Operation Manual page 116

Configuring the IO Controller
!Caution
Note
I/O Mapping Without Auto
Addressing
Note
Example
102
Enabling Auto Addressing has the immediate effect of re-allocating I/O modules of an
existing configuration, within each Input/Output area. The I/O modules are re-mapped
according to the algorithm described above.
Disabling Auto Addressing has no immediate effect on an existing I/O
mapping.
A disabled Auto Addressing feature has the following effects on I/O mapping:
• When adding new IO Devices or new I/O modules to an existing
configuration, the I/O modules will be mapped to the first I/O areas, but the
modules will be appended to the existing I/O mapping.
• When deleting a IO Device from the network configuration, or deleting I/O
modules from a IO Device, the deleted I/O modules will leave gaps behind
in the already existing I/O mapping. If after deleting an I/O module a slave
device still has more than one module configured, but these modules are
not in the same place, the DTM will attempt to re-map them together.
• Changing the address of a IO Device, of which already an I/O mapping
exists, has no effect on the existing mapping.
• Selecting an additional I/O module for a IO Device, in the presence of
already allocated I/O modules, will cause a complete re-map of all existing
modules if the total I/O does not fit within the space it is already occupying.
The modules are re-mapped to the next available location in the area,
leaving behind a gap in the existing I/O mapping. Subsequent I/O modules
of other slave device will remain mapped as before the module addition.
• When moving an I/O module from one area to another, they can be located
anywhere with in the target area. They are not re-mapped to the start of
that.
• When moving an I/O module from one area to another, the module leaves
behind a gap in the I/O mapping of the first area.
1 Gaps in the I/O mapping still contribute to the total size of an area,
although they do not contain valuable data. They therefore decrease
the total I/O capacity of the CS1/CJ1W-PRM21 PROFIBUS Master
Unit, and unnecessarily occupy PLC memory.
2 In the I/O data exchange with the PLC CPU, these gaps will contain
zeros.
The figure below illustrates the effects of re-allocating I/O modules, when Auto
Addressing has been disabled.
Section 7-4