1756-l72 Enhanced Redundancy problem

Our System configuration

1756-A4 with !1756-l72!1756-cn2r!1756-rm!1756-en2t!

1756-A4 with !1756-l72!1756-cn2r!1756-rm!1756-en2t!

stratix 2000 series Ethernet switch 1783-us08t (For FTSE communication and EN2T looping)

1794-acnr15 flex i/o's

So far redundancy is Ok and with 19.53 Flash and we have SYNC displayed on the secondary.

FTSE we have configured as OPC client with Local RSlinx as OPC master and configured Topic in OPC /DDE Topic Configuration.All Ok with the communication.


The Problem..

When we switchover the controller say we tripped one We have a change over time of 12 seconds in FTSE. Ie Value updates only after 12 seconds.Previous value is retained though.

But for digital outputs which are on control-net is having bump less transfer on switchover..We played with timeouts and Polled messages parameters in RSlinx Topic Configuration but no use.I really think 12 seconds is hard for the cost we have spend ..And we are stuck right here ..

Is that problem with the switch ..I mean do we need managed switch ?.Or with OPC server ie any other method of connection ?.

Any Type of Help would be Highly Appreciated ...Thanks alll.

12 seconds actually sounds pretty fast for an Ethernet ARP table to be changed in Windows.

Are you familiar with how ARP and Ethernet MAC ID's work ? Both the computer and the Ethernet switch need to know which MAC ID's are associated with which device and which physical port of the switch. Usually a switch adapts fast (a few packets from a different MAC ID will cause the table to flush) but a computer doesn't.

When the ControlLogix Redundancy system switches the IP addresses of the 1756-EN2T modules, the switch and the FTView Server's TCP/IP stack need to adapt to that change.

I'm not expert with the low-level mechanics of this, but the systems I've built with ControlLogix Redundancy on Ethernet generally had 20-30 seconds of "blind time" while the Ethernet switches updated their MAC tables and the computers updated their ARP tales.

On systems where we needed to provide visualization and alarming during the controller switchover, we used a ControlNet connection.

As with all things Ethernet-related, the best way to troubleshoot is to capture the traffic with Wireshark so you can see which services and actions are taking place on the network.

That was helpful indeed Mr.Ken Roach.I was really not aware of that ARP tables in the PC you have mentioned..Is there any other solution I mean using a manged switch so that the PC wont make troubles in switching ARP tables ..