ETY Operating Modes and Premium Hot Standby
Original instructions
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Overview
There are 4 ETY operating modes:
ETY and the Premium Hot Standby System Synchronization
The Premium Hot Standby and the ETY operating modes are synchronized by the conditions described in the following table.
CPU Module Status
HSBY State
ETY Operating Mode
Not present or unhealthy
N/A
Unassigned
Present and healthy
Primary
Primary
Present and Healthy
Standby
Standby
Present and Healthy
Offline
Offline
Any one of four events will affect the ETY operating mode. They occur when
If the ETY detects a duplicate address when it powers up, the PLC goes to its offline state and the ETY’s IP address goes to its default address.
Power-up and IP Address Assignment
An ETY obtains its IP address assignment at power-up as follows:
If the HSBY ETY mode is ...
Then the IP address assigned is ...
Standalone
from the ETY configuration table.
Primary
the configured primary IP address from the ETY configuration table.
Standby
the configured primary address from the ETY configuration table + 1.
Not powered to powered up
determined by which controller powers up first (after check remote, the second ETY takes IP address + 1), or if powered at the same time, by a resolution algorithm:
  • Lower copro MAC address: IP address/primary state
  • Higher copro MAC address: IP address + 1/standby state
Offline Event Table
If the HSBY ETY mode is ...
Then the IP Address assigned is ...
Primary to Offline
the configured IP address from the ETY configuration table if the peer controller does not go to Primary state
Standby to Offline
the configured primary address from the ETY configuration table + 1.
When the CPU stops, the HSBY ETY goes to the Offline mode. The IP address remains the same if the peer controller does not go to Primary state.
Power-up and Ethernet Services
The following table shows how the status of an ETY service is affected by the Premium Hot Standby state.
HSBY State
Status of ETY Services
Client Services
Client/Server Services
Server Services
I/O Scanner
Modbus Messaging
FTP
SNMP
HTTP
DHCP
Not powered up to power-up
Run
Run
Run
Run
Run
Run
Primary
Run
Run
Run
Run
Run
Run
Standby
Stop
Run
Run
Run
Run
Run
Offline
Stop
Run
Run
Run
Run
Run