ALTUS Nexto NX3004 User Manual

6. Redundancy with NX3030 CPU
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ATTENTION:
When the Active PLC goes out from the Run mode and goes to Not-Configured, if the other PLC
was forgotten in Stand-by state, it takes over as Active and switches off the PLC which has just gone
from Active to Not-Configured. In this case, thus, the off-line download can’t be completed because
the PLC connected to MasterTool is off.
When the off-line download finishes, it’s possible to restart the PLC program execution where the
application was downloaded (put in Run again). After a few seconds, this PLC takes over again the
Active state.
After this PLC takes the Active state again, the other PLC can go out from the Inactive state, e.g.
pressing the PX2612 STAND-BY button on it. This causes the transition of this PLC to the Not-
Configured state. This PLC remains in the Not-Configured state until the automatic project
synchronization finishes. Then, it goes to Starting state and back to Stand-by state afterwards.
Previous Planning for Off-Line Modifications without Process Control Interruption
The following section Previous Planning for Hot Modifications in Redundant PROFIBUS Networks
describes a very important procedure which allows the off-line modifications download without
interrupting the process control. Even though this procedure doesn’t apply to any modification that
demand off-line download, it applies to the most used modifications.
However, in order to apply this procedure, the projects must be developed with a previous planning,
especially for modification that affects the PROFIBUS network. The following subsections describe
such previous planning for modifications that affect the PROFIBUS network and also other
modifications.
Previous Planning for Hot Modifications in Redundant PROFIBUS Networks
Among the modifications that affect a PROFIBUS network and demand an off-line download, the
following are supported by the procedure which allows executing off-line downloads without
interrupt the process control, if the PROFIBUS network is redundant:
 Insert a new PROFIBUS network
 Insert a new Ponto Series remote
 Insert a new I/O module in a Ponto Series remote
 Modify parameters in Ponto Series remotes or in I/O modules in Ponto Series remotes
ATTENTION:
It’s possible to insert non-redundant remotes under a redundant PROFIBUS network, using the AL-
2433 module (ProfiSwitch), as the example shown on Figure 6-1. However, such non-redundant
remotes will suffer discontinuities (output deactivation) when the off-line download is executed.
Next, the planning steps that must start at the creation of a new redundant PROFIBUS network are
described.
Step 1 – Plan Future Expansion of the Remotes Inserted in the PROFIBUS Network Initial Version
At first, a list must be made of the I/O modules which compose each redundant PROFIBUS remote
from the Ponto Series, in the PROFIBUS network initial version. The list must have the position
where each I/O module is inserted in the remote rack.
Next, the future expansion of each remote must be planned. For that, a complementary list must be
made, consisting in I/O modules which might be inserted in the future. In it, the position where each
I/O module might be inserted in the remote rack must be listed.

ALTUS Nexto NX3004 Specifications

General

Brand	ALTUS
Model	Nexto NX3004
Category	Processor
Language	English