6. REDUNDANCY WITH NX3030 CPU
6.5.8.6. Step 6 – Physical Modifications Executing
At this moment, the physical modifications can be executed, such as:
Install a new NX5000 module. This can be done through a module hot-insertion in each half-cluster rack, then connecting
it to the Ethernet network
Install a new redundant PROFIBUS network. The NX5001 can be hot-inserted in each half-cluster rack. Then, the
redundant PROFIBUS network can be connected to them
Install a new Ponto Series redundant remote. In this case, a remote head must be installed at a time, e.g. first in the
network B and then in the network A:
• To install the head in the network B, it may be necessary to open the cable or the contacts, thus perturbing the
communication with the other heads already installed in the network B. Before doing that, all the operating active
heads must be placed in the network A and the operating reserve heads in the network B
• To install the head in the network A, it may be necessary to open the cable or the contacts, thus perturbing the
communication with the other heads already installed in the network A. Before doing that, all the operating active
heads must be placed in the network B and the operating reserve heads in the network A
Install an I/O module in a base previously reserved for it, in an existent remote
6.5.8.7. Step 7 – Download the Offline Modifications in the Non-Active PLC
At first, MasterTool must be connected to the Non-Active PLC (see MasterTool Connection with a NX3030 CPU from a
Redundant PLC section).
Next, the offline modifications must be downloaded. At doing it, the Non-Active PLC application is automatically inter-
rupted (goes out of the Run mode).
6.5.8.8. Step 8 – Set the Non-Active PLC Back to Run Mode to make go back to Stand-by State
The offline load being finished, the Non-Active PLC can go back to Run mode.
A few seconds later, the Non-Active PLC must assume the Stand-by state.
In case the PLC doesn’t assume the Stand-by state, the following problems may have caused this effect:
The modifications executed changed the redundant variables structure, which prevents the correct execution of the Re-
dundant Data Synchronization service. This can be verified through DG_NX4010.tRedundancy.RedDgnLoc.sGeneral_Diag
.bRedDataSync (0 = failure) diagnostics in the Non-Active PLC. In this case, the modifications must be undone, recov-
ering the previous project backup and restarting this procedure
Other problems may eventually prevent the transition to the Stand-by state, even though this is unexpected. In this case,
the diagnostics and the redundancy log must be observed
In case the PLC has assumed the Stand-by state, it’s recommendable to verify if the projects are different between the Active
and the Non-Active PLC. This can be made comparing the diagnostics DG_NX4010.tRedundancy.RedDgnLoc.sGeneral_Diag
.dwApplicationCRC and DG_NX4010.tRedundancy.RedDgnRem.dwApplicationCRC in the Non-Active PLC (the CRCs must
be different).
In case both projects are equal in the PLCs, it’s possible that the project synchronism disabling (step 5) has not being
properly executed. This can be verified through the diagnostic DG_NX4010.tRedundancy.RedDgnLoc.sGeneral_Diag .bPro-
jectSyncDisable, which must be true in the Non-Active PLC. If it isn’t true, the procedure must be returned to step 5.
6.5.8.9. Step 9 – Execute Switchover between Active and Stand-by PLCs
A switchover between the PLCs must be executed, e.g. pressing the STAND-BY button on the Active PLC. The Stand-by
PLC, which has a new project with the modifications, takes over as Active. The Active PLC, which has the old project, takes
over as Stand-by.
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