Redundancy for Premium PLC

[ballvietnam 0]

Hello everyone. I am trying to solve a problem like that : To make a device redundancy we have to use two PLCs, one primary and another is standby.We can solve this problem when we use PLC that support Hot - Standby function.for instance: Premium TSXH5724 or TSXH5744 or Quantum PLC support this function. But if We don't have these PLC we have to find another way. I have two PLCs premium TSX 573 634, one Ethernet OTB They connect to each other thought SWITCH. the protocol is modbus TCP. Two PLCs have the same program.When nothing happens only Primary control OTB and Standby just request status of Primary. When Primary fail, it means that : Standby can not recive signal from primary (the communication between primary and standby fail) so standby will take over to control OTB.I think the most importance is how we can detect primary PLC fail. Does anyone who interested in this problem, give your idea to solve this problem or who aldready solved plz share your solution with us. thank for your regard

[Crossbow 278]

Well if you choose not to use a truly designed redundant PLC, there's no guarantee on the switch. If the first PLC goes down, it's not going to run any code to communicate with the second. So how will the second know the first has crashed? Best you can hope for is use a constantly changing register in the PLCs (like incrementing a register each scan), transmitting over the network to the other PLC, and then in the other PLC compare it to see if it matches the last read. If that compare stays true for a few seconds, then either the PLC stopped or comm went down. There's a reason redundant systems were designed, and they have hardware designed to do this communication and control switching. They cost more, but there's a time and place where spending the extra money is more important than cutting corners.

[Henrique 0]

Another question: Are you going to make (or think about) a redundancy circuit for the OTB I/Os? I'm asking because, usually, most of problems happens on I/Os and Power Supplies. And, if you are using OTB I/Os, it means that your major concern is about cost, since OTB are the very cheap (entry level) remote I/Os, with not too much protection against short-circuit, over-voltage, surges, etc. PS.: I agree with Crossbow.

[ballvietnam 0]

first of all, I thank for your regard I know what you worry.I send you this document that I received from an expert in Schneider Electric.I hope you can find useful things.I think we have the same concept

[tragically1969 0]

I am very confused, in your title you asked about 'Redundancy for Premium PLC' then you post a PDF for the Momentum, how does posting a PDF for a different PLC platform solve your problem ?

[aggattapauer 2]

I suppose Momentum warm standby application is not for free such as there was an identical commercialized application for Premium with PL7 based on FIPIO communication. With Unity no warm standby application officially exist. I know someone has done an application working perfectly based on M340 hardware and ethernet I/O advantys STB (and they are planning to test new M340 remote I/O processor). I suppose the application is completely compatible with Premium as far as it is programmed with the same platform Unity. I'll check. Pay attention about Advantys OTB modbus timeout configuration: I'm not sure is configurable as STB via WEB server Xin Chao

[rajsiyer 7]

Avanti, my italian friend. I would very much like to know how your friend Xin Chao managed to get redundancy using M-340 and Advantys?. Please confirm that they have actually done this with M-340 and Advantys STB. Regards, best wishes and thank you very much for your earlier helf regarding Premium Hot standby Have a nice day Raj S. Iyer