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Questions about: Redundant CPs 443-1 & Modbus TCP

Created by: GregorZ at: 8/31/2007 9:56 AM (10 Replies)

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8/31/2007 9:56 AM	Rate (0)
GregorZ Posts: 1 Rating: (0)	Hello! I would like to connect redundant controller AS417-4-2H (6ES7654-2PG67-0XC0), which has 2 separate Ethernet CPs, to the Modbus TCP slave device (ABB AC800PEC controller) which has only one ethernet port. The configuration should work in case of failure of one of the controllers of AS417 configuration. 1.I believe that each controller of AS417 configuration should have a Modbus TCP FB loaded. Two simultanious links to the Modbus slave device are established from AS417 controllers. Is this common feature of Modbus TCP slave devices (two links at the same time) or is this special functionality which is not supported in all Modbus TCP slave devices? Does anyone have any experience in connecting redundant system to non-redundant Modbus TCP slave device? Could someone confirm similar working configuration? 2. Is it possible to use two different protocols in one Ethernet CP at the same time? (e.g: communication with Modbus TCP slave device and for SCADA communication using e.g. S7 protocol). Best regards, Gregor Attachment ModbusTCP.gif (402 Downloads)
GregorZ Posts: 1 Rating: (0)	Last edited by: CS Moderator at: 31.08.2007 11:49 new subject after splitting
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8/31/2007 12:44 PM	Rate (0)
J_Bell Posts: 5822 Rating: (412)	Dear Gregor, I admit I am not the Modbus TCP expert, but usually the Ethernet CPs support multiple Protocols. What I do not think is that this configuration works. As much as I know is the Modbus TCP driver not released for the redundant use. Best regards J_Bell
J_Bell Posts: 5822 Rating: (412)
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10/13/2008 8:53 AM	Rate (0)
Wüstenräuber Gold Member Joined: 10/3/2008 Last visit: 1/21/2025 Posts: 967 Rating: (127)	Dear GregorZ, 1. there is a product "OpenModbusTCP Redundant", which supports the single-sided redundancy (communication partner is alone) and the double-sided redundancy (communication partner is redundant). Product sheet see attachment. 2. It's not a problem to use different protocols in 1 Ethernet-CP at the same time. Wüstenräuber Attachment OpenModbusTCP_eng.pdf (355 Downloads)

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10/17/2008 3:56 PM	Rate (0)
callsg Posts: 17 Rating: (0)	I have already connect H-PLC to other plc in redundant modbus TCP. I think it is same to non-redundant modbus tcp The first.you said "that each controller of AS417 configuration should have a Modbus TCP FB loaded." It is wrong. the one controller of AS 417H should have two Modbus TCP FB. each modbus tcp FB connect aCP443-1.Becausea CPU can control everyCP. you can decide which CP443-1 isavailabe by diagnotic program. Then you can read date from the available CP.
callsg Posts: 17 Rating: (0)
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10/21/2008 2:06 PM	Rate (0)
J_Bell Posts: 5822 Rating: (412)	Hello callsg, may I ask you one thing... what is if the CPU you use for MODBUS TCP is switched to be passive? Is your MODBUS TCP Communication still running then? Best regards J_Bell
J_Bell Posts: 5822 Rating: (412)	Last edited by: J_Bell at: 10/21/2008 2:08 PM
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10/23/2008 3:10 AM	Rate (0)
callsg Posts: 17 Rating: (0)	J_Bell Hello callsg, may I ask you one thing... what is if the CPU you use for MODBUS TCP is switched to be passive? Is your MODBUS TCP Communication still running then? Best regards J_Bell Hello J_Bell, Certainly. It can run. First. you can write two FB of modbus-tcp for twoCP. If modbus TCP slave is single station. you can ask CP A to connet Modbus Slave. If It is right. you needn't CP B. if It's wrong. You can ask CP B to connect Modbus Slave again. total above. you write programmer in one cpu Ifmaster CPU is fail.The slaveCPUonly connect modbus slave in CP of slaveCPU. if CPU is only switched. It can't affect CP communication. Attachment ModbusTCP.JPG (346 Downloads)
callsg Posts: 17 Rating: (0)
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10/23/2008 11:38 PM	Rate (0)
J_Bell Posts: 5822 Rating: (412)	Hello callsg, well... I hope you still agree with me that this will fail as soon as either one of the following devices fail: The CPU / CPU Connection The Slave CPU itself The Rack with the CP’s configured to connect the MODBUS Device to. So actually there is no redundancy in the H-System. I hope you agree with me. Best regards J_Bell
J_Bell Posts: 5822 Rating: (412)
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10/24/2008 3:51 AM	Rate (0)
callsg Posts: 17 Rating: (0)	Hello J_Bell, I am sorry for cann't agree with you. please see attached document. Attachment Doc1.zip (354 Downloads)
callsg Posts: 17 Rating: (0)
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10/24/2008 12:10 PM	Rate (0)
J_Bell Posts: 5822 Rating: (412)	Hello, as far as I remember you wrote: ...The first.you said "that each controller of AS417 configuration should have a Modbus TCP FB loaded." It is wrong. the one controller of AS 417H should have two Modbus TCP FB.... So if just one PLC part of the H System hast the FB running... the Modbus will fail, as soon as this CPU fails, is this true? Best regards J_Bell
J_Bell Posts: 5822 Rating: (412)
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10/27/2008 2:40 PM	Rate (0)
callsg Posts: 17 Rating: (0)	J_Bell Hello, as far as I remember you wrote: ...The first.you said "that each controller of AS417 configuration should have a Modbus TCP FB loaded." It is wrong. the one controller of AS 417H should have two Modbus TCP FB.... So if just one PLC part of the H System hast the FB running... the Modbus will fail, as soon as this CPU fails, is this true? Best regards J_Bell If just one PLC part of the H system has only a Modbus FB running for his CP model. The Modbus will fail, as soon as this CPU fails. this is right! If the H system have two Modbus FB running for their two CP models. The Modbus will run, as soon as one CPU fails. Do you knowthe FB260 for Modbus TCP? what thing you can't understand now? Attachment tee.jpg (388 Downloads)
callsg Posts: 17 Rating: (0)
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