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S7-300 Software Redundancy didn't switchover when DP fail

Created by: edsel lin at: 3/6/2012 11:57 AM (10 Replies)

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3/6/2012 11:57 AM	Rate (0)
edsel lin Experienced Member Joined: 5/17/2010 Last visit: 2/21/2022 Posts: 80 Rating: (1)	I configure S7-300 software redundancy using CPU315-2DP and 2 racks of ET200M HF. For example I use 2 CPU, PLC-A & PLC-B. The redundancy already works when I stop the PLC-A, it will change to PLC-B as master. When I turn off the DP slaves (ET200M power supply) from CPU-A, the ACT indicator LED on ET200M switched. But when I check the PLC master didn't switch over. CPU-A run as a master with fault DP, CPU-B still standby while the DP status OK. I use the OB86 program with the SWR_DIAG program as on the example program. Is this correct? When I delete the OB86, the PLC master will switch. But it will make the CPU stop. What should I do to make the change over when one of the DP slave fails?

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3/6/2012 4:17 PM	Rate (0)
AlexZ60 Posts: 47 Rating: (3)	I used ET200 - IM153-2BA02-0XB0. My OB86: CALL "SWR_DIAG" DB_WORK :=1 OB86_EV_CLASS:=#OB86_EV_CLASS OB86_FLT_ID :=#OB86_FLT_ID RETURN_VAL :="FC102_RET"
AlexZ60 Posts: 47 Rating: (3)
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3/7/2012 2:24 PM	Rate (0)
edsel lin Experienced Member Joined: 5/17/2010 Last visit: 2/21/2022 Posts: 80 Rating: (1)	I already did that and same modules, except the FC102_RET. Where did it go? I only use a spare Memory Word (MW). Have you tried to make the ET200M fails, like turn off the power or disconnect the DP cables. It will not switch over.

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5/11/2012 4:28 PM	Rate (1)
SolutionFinder Posts: 559 Rating: (87)	Dear ace_sinergize, That is OK. If you CPU A is master & IM of A has become faulty then redundancy system will switchover IM only but not the CPU. Why you want the CPU to change from Master to Slave? This system will work perfectly. There will not be any problem. Attachment Control_Word_Status.pdf (230 Downloads)
SolutionFinder Posts: 559 Rating: (87)
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5/13/2012 2:38 AM	Rate (0)
edsel lin Experienced Member Joined: 5/17/2010 Last visit: 2/21/2022 Posts: 80 Rating: (1)	Dear SolutionFinder, The problem is when the IM fault, the input status all will be zero. For example, I have a program for valve and use interlock from pressure switch (DI). The master CPU will read from the fail IM which is zero, and then give the output zero. The reserve CPU will read from the run IM which is one, and give the output one. If I program the redundancy for the output, the master will override the DO status. Then the DO will be blinking, on and off. From the example program, the standby program does not execute the redundancy program by using a jump command. If I use this program, the DO will be off. Following the master program. What I want is the DO will on even when one of the IM fails, so that's why I want the CPU to changeover.

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5/13/2012 3:32 AM

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SolutionFinder

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ace_sinergize
Dear SolutionFinder,

The problem is when the IM fault, the input status all will be zero.

For example, I have a program for valve and use interlock from pressure switch (DI).
The master CPU will read from the fail IM which is zero, and then give the output zero.
The reserve CPU will read from the run IM which is one, and give the output one.

If I program the redundancy for the output, the master will override the DO status. Then the DO will be blinking, on and off.
From the example program, the standby program does not execute the redundancy program by using a jump command. If I use this program, the DO will be off. Following the master program.

What I want is the DO will on even when one of the IM fails, so that's why I want the CPU to changeover.

Dear ace_sinergize,

Thanks for your reply.

Have you defined the parameters for FC 100 as per your actual hardware configuration?

I am also attaching the file for your ready reference.

Please go through it and define paramters for I/O & IM like PIO_FIRST, PIO_LAST, SLAVE_NO, SLAVE_LEN, SLAVE_DISTANCE once again & see the result.

Always download the change in this parameter by deleting DB5 (Instance DB of FB 101 'SWR_ZYK') from the online CPU & after that you download change in the both the PLCs.

Attachment

FC_100.pdf (196 Downloads)

5/17/2012 8:04 PM	Rate (0)
SolutionFinder Posts: 559 Rating: (87)	Dear ace_sinergize, Any update please? Please reply.
SolutionFinder Posts: 559 Rating: (87)
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5/18/2012 4:41 AM	Rate (0)
edsel lin Experienced Member Joined: 5/17/2010 Last visit: 2/21/2022 Posts: 80 Rating: (1)	Dear SolutionFinder, Thanks for the reply. I already did that, and the configuration already same with FC100. Actually the redundancy already works, when I change the value in M memory or Digital Output in Master CPU, the value in Standby CPU also changed. No error code is given. The program for redundancy called between FB101, the program as in the example. So from this program, the Redundant program will not be execute when the CPU is standby. A DB5.DBX 9.1 // Check if station is Master JC END CALL "Program Redundant" //redundant user program END: NOP 0 SolutionFinder If you CPU A is master & IM of A has become faulty then redundancy system will switchover IM only but not the CPU. If you already said like that, that is what happen to my system. But this redundancy is not good enough, when one IM has failed the master will read from the faulty IM. Have you try that before? I wonder do we need to create the change over manually, using the bit DB10.DBX0 from the control word.

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5/18/2012 9:25 PM	Rate (0)
SolutionFinder Posts: 559 Rating: (87)	ace_sinergize Dear SolutionFinder, SolutionFinder If you CPU A is master & IM of A has become faulty then redundancy system will switchover IM only but not the CPU. If you already said like that, that is what happen to my system. But this redundancy is not good enough, when one IM has failed the master will read from the faulty IM. Have you try that before? I wonder do we need to create the change over manually, using the bit DB10.DBX0 from the control word. Yes My Friend, This is not the case if "one IM has failed the master will read from the faulty IM" Here we are maintaining redundancy with CPU as well with IM also. We are using active back plane connectors for IM. So Both IM talks to Both the CPU via active backplane connector. If You have connected profibus cable of CPU-A to IM-A & Profibus cable of CPU-B to IM-B. Then physically they are connected to individual CPUs. But internally all are in one loop. So It is not like that If IM fails then CPU reads data from that IM only. In this case data will be transferred from active IM-B.
SolutionFinder Posts: 559 Rating: (87)	Last edited by: SolutionFinder at: 5/18/2012 9:26 PM
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5/19/2012 5:54 PM	Rate (0)
manmeet Gold Member Joined: 1/3/2006 Last visit: 2/19/2024 Posts: 726 Rating: (71)	The system will work as Solution Finder says. To put this into test fail IM-A. Then activateone of the input of IM-B. Read this input in variable table it shall beTrue all the timeand notflickering between 0 and 1 as you believe.

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