ETY Configuration and Hot Standby
Original instructions
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Overview
Because a user can configure several ETY modules in each PLC, the monitored ETY modules that are dedicated to the ETY sync link must be configured in Control Expert.
NOTE: Only one ETY module can be dedicated to the ETY sync link in each PLC.
Description of the Hot Standby Solution
CAUTION
RISK OF INCREASE OF TIME TO SWAP
TSX ETYs must communicate with each other in order to swap IP addresses. Whenever possible, use of a switch (not a hub) to connect the TSX ETYs to each other or to the network. Schneider Electric offers switches. Contact a local sales office for more information.
Failure to follow these instructions can result in injury or equipment damage.
ETY Hot Standby allows automatic IP address swapping.
The TSX ETYs coordinate the swapping of IP addresses. After closing both the client and the server connections, the TSX ETY sends a swap UDP message to its peer TSX ETY. The sending TSX ETY then waits for a specified time-out (50 ms) for the peer swap of UDP messages. Either after receiving the messages or after a time-out, the TSX ETY changes its IP address.
NOTE: TSX ETYs must communicate with each other in order to swap IP addresses. Schneider Electric recommends that you connect the primary and standby TSX ETYs to the same switch for two reasons:
  • Communication failures between the TSX ETYs increases the time to swap
  • Connecting two TSX ETYs to the same switch minimizes the probability of a communication failure.
Actions of the ETY in the Premium Hot Standby System
WARNING
UNEXPECTED APPLICATION BEHAVIOR
Design your application so that unmonitored ETYs support communication only to noncritical parts of the application.
Failure to follow these instructions can result in death, serious injury, or equipment damage.
The TSX ETY waits for either a change in the controller’s Hot Standby state or the swap of UDP messages. Then the TSX ETY performs one of two Hot Standby actions.
If the TSX ETY...
It then...
Detects that the new Hot Standby state is either primary or standby
changes the IP address.
Receives a swap UDP message
transmits a Swap UDP message and swaps the IP address.
All client/server services (I/O Scanner, Global Data, Messaging, FTP, SNMP, and HTTP) continue to run after the switchover from the old to the new primary TSX ETY.
The failure of a monitored primary ETY module triggers a switchover. The failure of an unmonitored primary ETY module does not trigger a switchover.