Filter
Top Products
Using a Quantum IEC Hot Standby System
146
840 USE 106 00 January 2003
While Your System Is Running
Constant Internal
Monitoring
After your Hot Standby system has been started and is running normally, it
continues to function automatically. It constantly tests itself for faults and is always
ready to transfer control from the Primary to the Standby if it detects a fault.
Regular Data
Transfers
While the system is running, the module automatically transfers all state RAM to the
Standby unit at the end of each scan. This ensures that the Standby is aware of the
latest conditions and is ready to take control if needed.
If one or both of the links between the Hot Standby modules is not functioning, the
Primary controller functions as though no backup is available.
If the Primary controller fails, the Standby automatically assumes control of the
remote I/O network. If the Primary controller recovers from failure, and a power cycle
is completed, then it assumes Standby responsibilities. If it cannot recover, it
remains offline.
If the Standby controller fails, it goes offline. The Primary controller functions as a
standalone and continues to manage the I/O networks.