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Old January 30th, 2007, 07:18 AM   #1
PLC_talk
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S7 redundancy hangups!

Hello All,
First I tried browsing all the earlier posts to check for some solution, but can't find it.. so here is the problem

Situation 1 - S7-400H system in redundant mode, Works fine when both CPUs are in RUN. If the standby CPU is taken to STOP & then turned back to Run mode then it doesnot go back to RUN & the system runs in SOLO mode. Have to shutdown both the CPUs & turn them ON again to get back redundant running.
Situation 2 - Both CPUs working in RUN mode & any changes to Master CPU ladder, then again, if the standby CPU is taken to STOP & then turned back to Run mode then it doesnot go back to RUN & the system runs in SOLO mode. Have to shutdown both the CPUs & turn them ON again to get back redundant running.

Am I doing any procedural mistake or its some programming error?
It bugs me that as per manual the ladder shoulg get transfered from master to standby if the standby CPU is turned from RUN-STOP-RUN mode.


Any words of wisdom?

Thanks,
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Old January 30th, 2007, 07:27 AM   #2
PLC_talk
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Does anyone know which Siemens manual tells about the Event IDs & errors in the Diagnostic buffer.
One stupid question - There is a S7 software redundancy manual. Is it a strict no-no to refer if I am using s7400H H/W redundancy?
Some of the prerequisites in it are confusing me; e.g. Only IEC timers allowed , S5 timers will not work in redundacy system.

Any suggestions???
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Old January 30th, 2007, 09:57 AM   #3
JesperMP
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Quote:
Originally Posted by PLC_talk
One stupid question - There is a S7 software redundancy manual. Is it a strict no-no to refer if I am using s7400H H/W redundancy?
I have no experience with redundancy, but I would definitely ignore that manual and find the correct one.
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Old January 30th, 2007, 10:35 AM   #4
Marsupilami
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Thats strange behaviour. we have a S7-400H system running and we never saw such a thing.

As for an online change, we dont need to stop the standby CPU to copy the change to the standby CPU. when you download the change it is immediatly copied to both the CPU's.

the only limitation is that you cant download when Rack 0 is not reachable.

Regards,

Marsupilami
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Old January 30th, 2007, 01:07 PM   #5
sylent
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sync

Have had some experience with 400H's and usually if you are monitoring one such as in a VAT or ladder it will not let them sync up fully - or it sees it as a difference so if you power down the stand by and power it back up - they won't sync until everyone stops monitoring and you put the standby from stop to run. Also if you have a programming cable attached to one and not the other it will be fine if they are both running, but if one stops they won't be able to sync again because it sees a difference between the two - or at least this is my understanding of this behavior... Other than these few quirks they've been great.
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Old January 30th, 2007, 11:26 PM   #6
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Quote:
Originally Posted by sylent
Also if you have a programming cable attached to one and not the other it will be fine if they are both running, but if one stops they won't be able to sync again because it sees a difference between the two - or at least this is my understanding of this behavior... Other than these few quirks they've been great.
Sylent, Thanks for your suggestion. This is one thing I hadn't tried nor thought of!
Will let you know if it works this way.
Presently I am getting errors in diagnostic buffers as - #49A4 - Inconsistency in configuration data , & #530DSDB error.

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