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Redundancy issue

Created by: S3eed at: 2/8/2019 10:19 AM (4 Replies)

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2/8/2019 10:19 AM	Rate (0)
S3eed Member Joined: 2/4/2019 Last visit: 2/8/2019 Posts: 2 Rating: (0)	So we have a dual redundant S7-400 with 412-5H CPUs. The problem is they are all running as Masters. We have had issues with the communication to the control system because of data collision, according to one of the CPU's Diagnostics. We have found duplicated local to remote nodes which is the cause of the collision. Question is, what controls the operating mode of each CPU Master and Standby modes? Thank you ...sent from App

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2/12/2019 10:21 AM	Rate (0)
ameic Advanced Member Joined: 7/21/2010 Last visit: 7/31/2019 Posts: 54 Rating: (1)	Dear S3eed If you have configured the H System in a proper manner, the only reason that can makes both CPU Master is sync system between 2 CPU ( FH Module and Fiber Optic Cable ) , Please check : 1. system is configured as H system 2. all connection between CPUs are OK. Regards,

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2/27/2019 3:03 AM	Rate (0)
hdhosseini Diamond Expert Joined: 1/28/2009 Last visit: 8/23/2019 Posts: 6548 Rating: (1212)	Hello, So we have a dual redundant S7-400 with 412-5H CPUs. The problem is they are all running as Masters. We have had issues with the communication to the control system because of data collision, according to one of the CPU's Diagnostics. We have found duplicated local to remote nodes which is the cause of the collision. Question is, what controls the operating mode of each CPU Master and Standby modes? There is the checklist to consider while installing S7-400H CPUs,You can find it in section "4.3 Hardware assembly and commissioning of the S7–400H" of this manual: SIMATIC Fault-tolerant systems S7-400H The main points to consider are always: Check rack number of each CPU Keep both CPUs in STOP mode when you are not sure if the master standby works fine.This is important after start up. Both Fiber optic links interruption may result such a case.Please check them via LED on the CPU. Chapter 5 of the same manual you will find more about the information you can get from LEDs. I hope it helps, hdhosseini
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3/4/2019 10:44 AM	Rate (0)
WPLC012 Advanced Member Joined: 12/12/2018 Last visit: 8/21/2019 Posts: 22 Rating: (0)	I thing that you have a problem with the redundancy. You need to make a good config in HW config and also use the sync modules and the synchronization cables. Please check your configuration and the modules configuration and also the cables of synchronization.
	Best Regards, Wahbi
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6/30/2019 8:36 AM	Rate (0)
RKB202 Experienced Member Joined: 9/28/2017 Last visit: 8/24/2019 Posts: 54 Rating: (0)	There is a switch behind each s7-400h cpu to determine the rack number. Set the switch position to rack 0 or 1 for each cpu respectively. Set rack 0 for the cpu of rack 0And rack 1 for the cpu of rack 1. Thanks.

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