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Hello all,
I got a customer who used PcVue 10.0 SP1 to communicate with Siemens 300 using Siemens IP-ISO-S7. And, found that:
1. Send the command (e.g.@CMD) from PcVue side, in the PLC it changed within 1s, it's normal;
2. but, PcVue needs 10 seconds to get the changed status(e.g. @STATUS);
The command and status are in two separate frames, with 1s scan rate, even we changed the scan rate to 100ms for the status frame, nothing changed.
At the moment, i did not receive the CW trace. Do you know there is some settings to improve?
Thx a lot.
Posted : 17/04/2013 9:10 am
Yes, just wait the CwAudit traces first 😉
Posted : 17/04/2013 12:10 pm
Yes, just wait the CwAudit traces first 😉
here are the trace,please check the trace after 13:57.
Posted : 18/04/2013 9:17 am
may be you can give us your opinion first 😛
Posted : 18/04/2013 12:17 pm
may be you can give us your opinion first 😛
Maybe, the frame to read status is too big. 🙁
It's very strange, because normally PcVue reads data faster than write the command.
Posted : 18/04/2013 12:44 pm
I can see this:
[13:58:09:234][0360] Cmd Dump: [ComObj: ] [Type: ] [Reason: ]
then
[13:58:12:281][0360] Cmd Dump: [ComObj: ] [Type: ] [Reason: ]
meaning we read the data 3s after writing.
And then the READ is
[08000000][13:58:23:031][0360] Cmd Dump: [ComObj: ] [Type: ] [Reason: ]
[08000000][13:58:34:484][0360] Cmd Dump: [ComObj: ] [Type: ] [Reason: ]
Meaning you have a read request every 11s. So I am not surprised that, sometimes, you see the value 10s after a write.
What your customer can try is to activate the mode ReadAfterWrite using the Scada Basic function CIMWAY("READAFTERWRITE"...)
Then it will send a read request everytime after a write request.
Posted : 19/04/2013 7:35 am
Thank Nico!
So, I just need to suggest the customer to create a SCADA Program to trigger the ReadAfterWrite function for each frame. And then configure the SCADA Basic in the Stations Startup.?
🙂
Posted : 19/04/2013 8:05 am
Yes but only the frames that you can write.
By the way, it should be good to investigate why a frame set to 1s polling is really polled every 11s...
Posted : 19/04/2013 8:38 am
But what about the command and status are not in the same frame?
For the 10s, I referred to Emmanuel, if i have news, I'll update the ticket.
Posted : 19/04/2013 10:58 am
Shu Quan, this is normal. The protocol allows you to Read OR Write. So, if you set a control then PcVue just send a Write request.
Posted : 19/04/2013 11:11 am
Just to update the ticket:
With Emmanuel's help, the problem is solved.:)
It comes from the "message time out" parameter which the customer set it to 1s.
Posted : 26/04/2013 11:25 am
Arrrgghh!
The classic mistake!
Posted : 29/04/2013 12:34 pm
🙁
Posted : 03/05/2013 2:03 pm