6. REDUNDANCY WITH NX3030 CPU
6.6.2.3. Alert before Logging in to Non-Active CP
In normal circumstances, it isn’t usual MasterTool to connect to the Non-Active PLC. This way, when there’s a try to
execute this type of command, MasterTool sends the following warning:
"You are logging in to a Non-Active PLC, and this is not usual. Are you sure you want to execute this command?"
On the other hand, there are circumstances (not so usual) in which it’s necessary to login in the Non-Active PLC, and in
these cases the user must authorize the login. Such circumstances may occur, e.g.:
For initial configurations, as described in Initial Downloading of a Redundant Project section
For downloading offline a different project in the Non-Active PLC, as described in the Exploring the Redundancy for
Offline downloading of Modifications without Interruption of the Process control section
For monitoring or forcing the non-redundant variables in the Non-Active PLC
6.6.3. Redundancy Diagnostics on NX3030 CPU Graphic Display
Many diagnostics related to redundancy can be observed on the NX3030 CPU display.
6.6.3.1. CP Redundancy Status
The PLC redundancy state, described in Redundant CPU States, is seen in the three initial characters on the main screen
second line, as shown in the section Graphic Display. The display screen is presented on initialization and again a few seconds
after the navigation is finished (without pressing the NX3030 CPU button).
6.6.3.2. Screens below the REDUNDANCY Menu
There’s a menu called REDUNDANCY, where below it there are several screens. The description and access of these
screens are available in the Configuration – CPU’s Informative and Configuration Menu section.
6.6.4. Redundancy Diagnostics Structure
The NX4010 module diagnostics area is mapped over direct representation %Q variables, and defined symbolic through
the AT directive, in the GVL Module_Diagnostics.
This section is divided in two parts:
DG_NX4010.tGeneral: General diagnostics for NX4010 operation. They are described in the Redundancy Link Module
Technical Characteristics – CE114900
DG_NX4010.tRedundancy: Redundancy specific diagnostics which are described within the section. This item is di-
vided in other 6 data structures:
• RedDgnLoc: Has redundancy diagnostics of the local PLC (connected), e.g. the PLC redundancy state. This
section is described in Redundancy Diagnostics
• RedDgnRem: It’s a copy from the other PLC RedDgnLoc, received through Synchronism channels NETA / NETB.
This way the local PLC has access to the remote PLC diagnostics. This section is described in Redundancy
Diagnostics
• RedCmdLoc: Has redundancy commands generated in this PLC (local), for instance, through write commands
from a SCADA system or generated in POUs in this PLC (ActivePrg or NonSkippedPrg). This section is described
in Redundancy Commands
• RedCmdRem: It’s a copy from the other PLC (remote) RedCmdLoc, received through Synchronism channels
NETA / NETB. This section is described in Redundancy Commands
• RedUsrLoc: Used to allow the user to exchange information between PLCA and PLCB. This section is described
in User Information Exchanged between PLCA and PLCB
• RedUsrRem: Used to allow the user to exchange information between PLCA and PLCB. This section is described
in User Information Exchanged between PLCA and PLCB
It is important to stress that the redundancy diagnostics structures are refreshed only when occurs, with success, a new data
synchronization. Therefore, until a new synchronization doesn’t occur, the diagnostics will remain with the last read value.
Furthermore, the diagnostics structures from the remote PLC are read only, that is, values written to these structures will
be overwritten in the next synchronization. Thus, is not possible to use the RedCmdRem structure to execute a command in
the remote PLC. Always use the structure RedCmdLoc to execute commands.
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