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Topic starter
Hello,
With two redudants historical servers, a customer uses sql server to record data.
The trouble that he meets is : for a same chrono and same variable, PcVue records two different values in each server.
Any experience ?
P.S.: the clock is the same between servers.
Posted : 03/08/2012 5:35 pm
Brice you must describe the architecture more in details.
What's the protocol? Each server is communicating with different devices?....
Posted : 07/08/2012 10:06 am
Topic starter
Hi,
In this case, the value recorded is internal (chrono type)...
There are two redundant servers (historical and real time), ten clients, protocol used is modbus IP.
Thank you.
Posted : 07/08/2012 12:27 pm
Real time and archives server associations are Single or Multiple Active?
Posted : 07/08/2012 4:20 pm
Topic starter
Real time : single (without internal variables switching)
Archives : multiple (9.0 SP1)
Posted : 07/08/2012 4:56 pm
Hmmm strange.
If the variable is produced by the association then the VTQ should be the same everywhere.
How the variable is set?
Posted : 08/08/2012 6:35 am
Topic starter
Very strange !
It's a register variable configured as a chrono so set thanks an alarm variable.
I have checked the variable and the server and client list are well set.
Posted : 08/08/2012 12:54 pm
Hmmm the fact that's a chrono generates a special situation. Look, when the bit starts the chrono it starts in all stations. So, if you have only 2 servers (no client) then you can imagine your register changing both sides and then you have 2 events at the same time! Worst, imagine you have 5 clients...
To solve your issue you must manage to trigger the register only on the Active station.
Posted : 09/08/2012 6:55 am
Topic starter
The variable which triggers the chrono is an alarm that communicates in modbus.
Both are configured with server list, normally the active server is the only one which can read the alarm and set the chrono.
Am I in the wrong way ?
Posted : 09/08/2012 6:03 pm
Hi Brice,
You mentionned "without internal variables switching"
Does it mean that the option is set(not the default)?
Because in this case the variable values behavior between the servers of the association is the same as for a multiple active servers association : internal vaiables between servers are not shared until you set the option "broadcast" for the variable.
You may have checked that but do the value of the variable is the same in the application explorer of the 2 servers?
Francois
Posted : 09/08/2012 7:35 pm
Yes maybe you are wrong. Of course it should be like that, but if there is a bug then it can explain why you have this strange result.
Look the process I suspect:
1. Bit is set in PLC
2. Bit set in Active server
2a. Start Chrono on active server
2b. Bit set is broadcasted to the clients and Stan-By server
2aa. Start the chrono on clients and stand-by server: This is the to be checked with Dominique
Posted : 10/08/2012 6:58 am
Nico, when the option "without internal variables switching" is set for the association the internal variables ARE NOT broadcasted between the servers exept if you have a list of servers conatinaing each server instead of having a list containing the name of the association.
Read the document I upload...
My guess is that the value of the chrono is not the same on eaxh station
Posted : 11/08/2012 12:52 am
Topic starter
Hello,
to close the subject. I adviced the customer to change redundancy option but i don't have feedback for 7 months so I think it's okay.
Thanks
Posted : 19/03/2013 6:13 pm