6. Redundancy with NX3030 CPU
325
At first, the parameter “ %Q Initial Address of Module Diagnostics Area” must be modified in the
first NX5001 module, as shown on the table on the next figure. The planned initial address must be
used for the diagnostic %Q variables area.
Second, the first network I/O module must be found, starting with the NX5001, which allocate %I
variables for inputs. At finding it, the correspondent “Address” parameter must be altered.
Third, the first network I/O module must be found, starting with the NX5001, which allocate %Q
variables for outputs. At finding it, the correspondent “Address” parameter must be altered.
ATTENTION:
At this moment it’s recommended to verify the allocated address range for the 3 variable areas,
verifying if the final addresses of each area are within the planned range, and if there’s a good free
area for expansion for new future remotes insertion.
Previous Planning for Other Hot Modifications
There are other hot modifications which, though they don’t affect the PROFIBUS network, also
demand off-line downloading. Next, it’s presented some examples of this type of modifications
supported by the procedure which allow executing modifications off-line download without
interrupting the process control:
NX5000 modules insertion (Ethernet)
Ethernet or Serial communication I/O driver insertion
Ethernet or Serial communication I/O driver new mapping insertion
On the other hand, the previous examples of modifications imply the direct representation %I and
%Q variables allocation for diagnostics, inputs and outputs similar to discussed in step 3 from the
previous planning for hot modifications which affect the PROFIBUS network (see Step 3 – Allocate
%I and %Q Variables Areas for the PROFIBUS Network considering Future Remote Expansion).
This way, at inserting the NX5000 module, or an I/O Ethernet or Serial driver, the allocation of the 3
following areas must be planned for the inserted device:
%I variables area for inputs
%Q variables area for outputs
%Q variables area for diagnostics
The Step 3 – Allocate %I and %Q Variables Areas for the PROFIBUS Network considering Future
Remote Expansion section shows an example of group allocation of these areas, including
PROFIBUS networks and an I/O driver (Modbus TCP server).
Incompatibility of Applications
If the areas to be used in the future not be planned properly, the redundant memory areas may have to
be altered, thus generating a incompatibility between the applications. This will result in only on PLC
to remain in the Active state, with the other PLC remaining Inactive, without the possibility of
synchronizing redundant data or application between the two PLCs.
This incompatibility is informed by the redundancy diagnostics at:
DG_NX4010.tRedundancy.RedDgnLoc.sGeneral_Diag.bApplicationIncompatible.
This diagnostic is active when the download of a new application is done to one of the PLCs, usually
the Non-Active, with one of the following changes:
Changes in the redundant memory areas, configured in the parameters of the NX4010 module
Changes (create or remove) in the symbolic redundant variables, declared in redundant POUs or
redundant GVLs
It is important to stress that, to make changes in symbolic redundant variables, the incompatibility
problem will occur only if a new application download is done to one of the PLCs. In case that the
modifications in symbolic redundant variables, and all the other modifications made in the project, fit
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