Omron CJ Series Operation Manual page 183

 Enable/Disable Auto Addressing
The Auto Addressing feature can be disabled in the CJ1W-PRM21 Master DTM. Perform the follow-
ing sequence to control Auto Addressing.
1
Open the CJ1W-PRM21 Master DTM - Configuration User Interface.
2
Select the Master Setup tab.
3
Enable/Disable Auto Addressing by selecting/deselecting the Auto Addressing checkbox in
the Support box.
4
When Auto Addressing is being enabled, a warning message is displayed, informing the user of
the effects of enabling Auto Addressing.
Precautions for Correct Use Precautions for Correct Use
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.
Note Disabling Auto Addressing has no immediate effect on an existing I/O mapping.
 I/O Mapping Without Auto Addressing
A disabled Auto Addressing feature has the following effects on I/O mapping:
• When adding new slave devices or new I/O modules to an existing slave 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 slave device from the network configuration, or deleting I/O modules from a
slave 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 and these
modules are not in the same place, the DTM will attempt to remap them together.
• Changing the address of a slave device, of which already an I/O mapping exists, has no effect on
the existing mapping.
• Selecting an additional I/O module for a slave 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.
Note 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 CJ1W-PRM21
PROFIBUS Master Unit, and unnecessarily occupy CPU memory.
2 In the I/O data exchange with the CPU, these gaps will contain zeros.
The figure below illustrates the effects of re-allocating I/O modules, when Auto Addressing has been
disabled.
CJ-series PROFIBUS Master Unit Operation Manual for NJ-series CPU Unit (W509)
5 Operation
5
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