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Old May 27th, 2005, 01:06 PM   #1
United Arab Emirates

sanjay_snj is offline
Join Date: Jan 2004
Location: ABU DHABI
Posts: 36
Update Totalizer In Both Cpu

hi all !

can any one help me out !!!!!

i m using 2 nos. of 315-2DP cpu in a redundant configuration. actually i do not know it is hot redundant or any other redundancy. it is configured using cpu 315-2DP and IM360 & IM361. All the I/Ps (Rack No.1) and Outputs cards(Rack No.2) are redundant.When I put one cpu in stop, all outputs are getting off and the other cpu taking over the control in 25-30 secs.

The values are updating in TP170a operator panel also using cpu314 (called ALNAR1)

my prolem is when when one cpu is in line (called ALNAR 2), it is having one totalizer which is totalising the total flow value, read in one DB. When the cpu change over due to any problem, the totalizer value is not getting updated in another cpu (ALNAR3)and i am getting different totalizer value in both the cpu.

can any one help me out in keeping both the totalizer values synchronised .


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Old May 28th, 2005, 12:24 AM   #2

dchartier is offline
Join Date: May 2003
Posts: 1,539
Hello Sanjay;

Siemens offers a software Redundancy package for S7 CPus (it is the only option for redundancy for the S7-300 CPUs). This illustrates the basic principle:

Now, it appears from your description that you are not using this package and that you have some kind of homemade system checking switchover between CPUs, probably using a lifebeat signal to determine if the master CPU is actve.
At this time I have to say that synchronisation between the values read by each CPU do not seem to be controlled. We need details on how the information is exchanged between the CPUs in your system. Are all I/Os simply duplicated (hard-wired ) to each CPU? In that case, how do you make sure that the same data is read between the CPUs? Is there a network linking both CPUs? If so, you could transfer the totalizer value from the master CPU to the Stand-by over communication link (along with all pertinent data for switchover control);use the hard-wired info on the stand-by CPU only when it takes control. But if you are devising the system by yourself, you face a lot of data validation problems.
Please don't hesitate to come back to the foru\m with more details on your harware and software configurations. With more details, we can give more informed opinions.
Hope this helps,
Daniel Chartier
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Old May 29th, 2005, 02:15 AM   #3
Amr Hassan

Amr Hassan is offline
Join Date: May 2005
Posts: 340
To my knowledge u must use ET 200 M with a redundant bundle of IM153-2 to make sure that the inputs are accessed by both CPU's
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