Redundant Networks
Original instructions
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Introduction
You can connect Quantum S908 remote drops to redundant Quantum networks. The redundancy is retained when you migrate the Quantum network to an M580 architecture because the 140CRA31908 adapter module assumes the redundancy tasks of the Quantum CPUs.
Process Overview
The migration of a redundant Quantum network into a redundant M580 architecture is described in general stages:
Stage
Description
1
Assemble a Redundant Quantum RIO Network: Build a redundant Quantum network that includes Quantum S908 remote drops.
2
Assemble a Redundant Quantum EIO Network: Build a redundant Quantum network that includes both Quantum S908 remote drops and X80 remote drops.
3
Complete the Migration: Replace the Quantum CPUs in the above example networks with 140CRA31908 adapter modules, and add redundant M580 CPUs in local racks.
These stages are described in more detail below.
Assemble a Redundant Quantum RIO Network
This redundant Quantum RIO network is connected to Quantum S908 remote drops. The 140CRP93•00 communications module facilitates S908 communications with modules in the S908, SY/MAX, and 800 Series remote drops:
1
Quantum primary and standby CPUs on local racks with a fiber optic link 
2
140CRP93•00 communications modules with redundant connections to the Quantum S908 remote drops 
3
140CRA93•00 adapter module on a Quantum S908 remote drop
NOTE: The configuration of each Quantum CPU is identical. For information about redundant Quantum networks, refer to the Modicon Quantum Hot Standby System User Manual.
Assemble a Redundant Quantum Network
Add X80 remote drops to the redundant network (above):
Step
Action
1
Add a 140CRP31200 communications module to each local rack in the redundant Quantum network.
2
Add an X80 remote drop with a Quantum adapter module to the main ring.
3
Add an X80 remote drop with an M580 adapter module to the main ring.
4
Build the Control Expert application and download it to the Quantum CPUs.
Result: The 140CRP31200 modules (not the CPUs) connect the local rack to the Quantum main ring to facilitate Ethernet communications with the X80 remote drops:
1
Quantum primary and standby CPUs on local racks with a fiber optic link 
2
140CRP31200 communications modules 
3
140CRP93•00 adapter modules with redundant connections to the Quantum S908 remote drops 
4
BMECRA31200 adapter module on an X80 remote drop containing an M580 adapter module 
5
140CRA31200 adapter module on an X80 remote drop containing a Quantum adapter module 
6
140CRA93•00 adapter module on a Quantum S908 remote drop
Complete the Migration
Complete the migration of the redundant Quantum network (shown above) to an M580 architecture:
Step
Action
1
Remove the Quantum CPUs from the racks in the order that is opposite to their installation.
2
Place the 140CRA31908 adapter modules in the slots from which you removed the CPUs.
3
Add redundant M580 CPUs in local racks.
NOTE: The configurations of the redundant M580 CPUs is identical.
4
Connect the main ring to the M580 CPUs.
5
Remove the 140CRP31200 communications modules.
6
Modify your Control Expert application as necessary.
7
Download the Control Expert application to the M580 CPUs.
Refer to the EcoStruxure™ Control Expert, M580 Application Converter, User Guide.
Result: A 140CRA31908 adapter module (not a Quantum CPU) connects to the main ring. The M580 CPUs now manage the network and the 140CRA31908 modules:
1
M580 primary and standby CPUs on local racks with a fiber optic link 
2
140CRA31908 adapter modules 
3
140CRP93•00 communications modules 
4
BMECRA31200 adapter module on an X80 remote drop containing an M580 adapter module 
5
140CRA31200 adapter module on an X80 remote drop containing a Quantum adapter module 
6
140CRA93•00 adapter module on a Quantum S908 remote drop
Primary 140CRA31908 Election
When you migrate a redundant Quantum application to the M580 architecture, replace the Quantum CPU with a 140CRA31908 adapter module. The system assigns the role of I/O master to the first healthy 140CRA31908 module that it detects, but you can manually assign that role with one of these methods:
The internal state of the 140CRA31908 module is set to primary when it is the I/O master. In that case, the 140CRA31908 module can perform these tasks:
Only one 140CRA31908 module can serve the role of I/O master at any time. The other (not master) 140CRA31908 module performs these tasks:
Switchover
A 140CRA31908 module switchover is triggered by loss of communication between the CPU and the master 140CRA31908 module.
The CPU status is added to the input phase of the PLC scan as part of the INPUT assembly. The change of primary is sent to the 140CRA31908 module during the OUTPUT phase of the PLC scan. Therefore, the 140CRA31908 module switchover takes place over a maximum of two CPU scans.
The switchover is driven by the system or the application:
System-driven switchover:
In a redundant 140CRA31908 module configuration, the CPU can drive a 140CRA31908 module switchover according to the status of both 140CRA31908 modules.
There is a case in which neither 140CRA31908 module can drive the I/O modules. When the master 140CRA31908 module loses communication with all Quantum S908 remote drops, the RIO status from the master 140CRA31908 module is unhealthy. Therefore, the standalone CPU or the primary CPU operates a 140CRA31908 module switchover and assigns the role of I/O master to the other 140CRA31908 module. If the new I/O master 140CRA31908 module cannot properly drive the I/O modules, it reports an unhealthy RIO status to the CPU. In that case, the CPU assigns the role of I/O master to the other 140CRA31908 module. The CPU repeats this loop until one of the two 140CRA31908 modules is able to drive the I/O modules.
Application-driven switchover:
You can use system bit %S88 to reassign the master of the I/O points. When %S88 is set, the system triggers a 140CRA31908 switch over and assigns the role of I/O master to the other 140CRA31908. The system then resets %S88.
NOTE: In redundant 140CRA31908 module configurations, check the status of the redundant 140CRA31908 module before a switchover is triggered. If the redundant 140CRA31908 module is not healthy, the system does not allow the switchover (even if %S88 is set).
NOTE: The impact of the 140CRA31908 module on the redundant operating mode is discussed in the operating modes chapter.
Master 140CRA31908 Module Selection
Only one 140CRA31908 module is assigned the I/O master at any time. The master 140CRA31908 module can perform these tasks:
In redundant systems, the 140CRA31908 module that is not the I/O master can perform these tasks:
EIO Support
In the M580 redundant architecture, the detection of an I/O error can cause a CPU switchover when all of these conditions are true:
The detection of an I/O error on the S908 network does not cause a CPU switchover, but it can cause a 140CRA31908 module to switch when these conditions are true: