6. REDUNDANCY WITH NX3030 CPU
6.5.8.10. Step 10 – Projects Synchronism Enabling in the Active PLC
In the step 5, the project synchronism was disabled in the Non-Active PLC. It can be observed this PLC is now in Active
state.
In this step, the project synchronism must be enabled again in this PLC. The screen and methodology used for it were
described in the section Project Synchronization Disabling. But this time we need to select the “Enable” option from the
combo-box. MasterTool must be connected to the Active PLC (see MasterTool Connection with a NX3030 CPU from a
Redundant PLC section).
After enabling the project synchronism in the Active PLC, the user must verify if this command was successful, verifying
if DG_NX4010.tRedundancy.RedDgnLoc.sGeneral_Diag.bProjectSyncDisable = 0, in the Active PLC.
As soon as the project synchronism is enabled again, the following action sequence is expected:
The Non-Active PLC (Stand-by state), which already knows the different between both projects; goes out from the
Stand-by state and goes to the Not-Configured state
The modified project (new) is copied from the Active PLC to the other, temporarily in Not-Configured state
As soon as the projects are synchronized again, the Not-Configured PLC goes to Starting state and then it’s supposed to
go back to Stand-by state
6.5.8.11. Step 11 – Optional Reorganization of PLC and PROFIBUS Networks in Active State
At the end of the procedure, for standardization or organization reasons, the user may execute a switchover for the PLCA
assumes as Active, and for all remotes PROFIBUS heads in Active state are in the network A.
6.6. Redundancy Maintenance
6.6.1. Modules Hot Swapping in a Redundant PLC
In case of failure in a module from one of the PLCs (PLCA and PLCB), the module hot swapping may be necessary,
without interrupt the process control. For that, the following steps must be followed:
Verify if the half-cluster which won’t be modified is in Active or Stand-by state, allowing it to take the process control
To put the half-cluster having its module changed in Inactive state, through the Redundancy Control Panel PX2612 or
the Redundancy Commands
Execute the necessary exchanges in the Inactive half-cluster, as indicated in the CPU Configuration - General Parameters
- How to do the Hot Swap section
To put the half-cluster back to Stand-by or Active state, according to necessity
6.6.2. MasterTool Warning Messages
When MasterTool is with a redundant project open, or when it’s connected to a NX3030 CPU identified as PLCA or PLCB,
some special warning messages may occur, as described in the following subsections.
6.6.2.1. Blocking of Redundant or Non-Redundant Project Download
MasterTool doesn’t allow the download of a redundant project, unless the CPU is NX3030 and is identified as PLCA or
PLCB (see Identification of an NX3030 CPU section).
On the other hand, MasterTool doesn’t allow the download of a non-redundant project in a NX3030 CPU identified as
PLCA or PLCB.
In case any of these illegal actions is tried, MasterTool warns with a correspondent message.
6.6.2.2. Warnings before Commands which may stop the Active PLC
Some commands, as the following, may stop a PLC:
Offline load after Online / Login
Debug / Stop
Debug / New Breakpoint
Online / Reset (Warm, Cold, Origin)
In case MasterTool is logged to the Active PLC, and one of these commands is tried, before sending it to the Active PLC,
MasterTool sends the following message and waits for authorization:
"If the other PLC is in Stand-by State, it will assume as Active and turn-off this PLC. If not, this won’t happen, but the
automated process will no longer be controlled."
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