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SIMATIC S7-400 / S7-400H / S7-400F /FH

S7400H runing slow in redundant mode

Thread Starter: kinus123   Started: 5/8/2012 9:10 AM   Replies: 6

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  5/8/2012, 9:10 AM
kinus123
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Hello Everyone
One of my S7400H on the plant acting strange: it's running much slower in redundant mode, then in solo mode (f.e. refreshing data when faceplate is opened, in solo mode: less the 1 second, in redundant mode: sometimes about 4 seconds).
The CPU it not overloaded (about 30% load). I increased "Monitoring times" H Parameters in HW Config, I modified "Scan cycle load from communication" (increasing/decreasing) but it make no change in speed on CPU.
The CPU has lots of AS-wide interconnection.
Somebody has an idea what is going on?
Best regards
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  5/8/2012, 9:32 AM
Eastern
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Hello
       I think you can try H Parameter option in hardware configuration.
In the "H Parameters" tab you can set the parameters for the extended CPU test on an H system and times for connecting and updating.

aximum Number of Attempts

The maximum number of attempts to update the standby CPU is displayed. An attempt to update the CPU is interrupted when one of the monitoring times runs out. As long as the maximum number of attempts has not been used up, the CPU initiates an update again after the "Waiting Time between Two Attempts."

Cyclic Interrupt OB with Special Handling

The special handling of the cyclic interrupt OB consists of the OB being called by the operating system separately after all interrupts have already been disabled. The additional call shortens the time during which critical I/O components are not being processed. A "0" means: no cyclic interrupt OB with special handling.
Make sure that the cyclic interrupt OB whose number you enter has a priority greater than 15. Only then will it be called immediately before the start of the disabling time for priority classes > 15.

Waiting Time between Two Attempts

If an update fails because a monitoring time has been exceeded, the CPU continues to run in solo operation and tries again after the displayed waiting time to update the standby CPU.

http://support.automation.siemens.com/WW/view/en/25909684/faq




=== Edited by Eastern @ 5/8/2012 9:33 AM [GMT ] ===
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  5/10/2012, 8:53 AM
kinus123
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Hello
I'm using opition "0" in "Cyclic Interrupt OB with Special Handling", I don't need it. I think that changing  this options has no infuence on speed of CPU.

Somebody has an idea?

Best regards
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  5/10/2012, 9:34 AM
VishP
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Dear Kinus,

Are u sure that CPU is slow due to redundant mode only? I mean, do you have any communication fault or programming error?

If possible clear the memory and load the program again. Aslo restart a CPU in redundant mode.

There are some information required for better analysis...Is this new installation or old running? What is the application? Who are the communication partners and on which network?

Rnf:lblSmileyTooltip_ VishP.
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  5/10/2012, 9:48 AM
H-H
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Hello kinus123,

kinus123 wrote:
One of my S7400H on the plant acting strange: it's running much slower in redundant mode, then in solo mode (f.e. refreshing data when faceplate is opened, in solo mode: less the 1 second, in redundant mode: sometimes about 4 seconds).
Are you sure that WinCC connection has been configured as S7-Fault-tolerant connection?!
Just make sure you have this kind of connection and make sure that tags in WinCC are inside the named connection.
kinus123 wrote:
The CPU it not overloaded (about 30% load). I increased "Monitoring times" H Parameters in HW Config, I modified "Scan cycle load from communication" (increasing/decreasing) but it make no change in speed on CPU. 
The CPU has lots of AS-wide interconnection.
Somebody has an idea what is going on?
What is your CPU and how many connection resources do you use?
Can you remove these AS connections and test the CPU with WinCC in this case?


kinus123 wrote:
Hello
I'm using opition "0" in "Cyclic Interrupt OB with Special Handling", I don't need it. I think that changing  this options has no infuence on speed of CPU.
It's ok as you are using option 0. The special handling is mainly used with fail safe systems and it is not related to your problem.

Best regards,

H-H
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  5/10/2012, 9:55 AM
kinus123
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Hello
The instalation is new, and about the start up, so I'm able to clear the memory.
I don't have any programing errors, the CPU is working ok redundant and solo mode, only different is the in redundant mode it works slower. The application is not time relevant, it's a gas storage plant, communication partners are other S7400 in the plant (there are 9 of S7400),  the communication runs over Industrial ethernet, s7 fault tolerent connection.
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  5/10/2012, 10:34 AM
kinus123
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Hello H-H
For sure all wincc connection are s7 fault tolerant, and the wincc tags are in named connection.
If I check "Communication" in CPU Diagnostic, then: Connection resources Maximum - 64, not used - 53. The CPU is S7417-4H.
Removing the AS interconnection won't be easy.
I forgot to say, that in redundat mode the speed of the cpu is not constance, i mean that sometimes it is a bit faster, sometimes slower.
In H Parameters there is "Test cycle time", I have 90 min here, does anybody knows what do going on during this test, and how long does it takes? Mayby during this test the CPU is running slower?
I have recalcualate the H Paramteres "Monitoring times", it was standard 8000, 3200, 800, 120, now it's 22300, 8920, 2230, 120, it helps a littel, but still redundant mode it slower.
best regards
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