Scan Time

Viewing 15 posts - 1 through 15 (of 15 total)
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  • #8500
    AvatarRich Ex
    Participant

    Hi Friends ,
    I seem to have an issue catching a single pulse . My Scada unit offers me a single pulse for a channel which I use to start a calculation . Thing is sometimes the program does not see the pulse . I am wondering if its the scan time of Rapid Scada … not sure how this works , is it like a PLC and takes time to work through all the Channels , I have 268 channels mostly calculated types with 32 real input types .

    Thanks
    Rich

    #8501
    Avatarmanjey73
    Participant

    Where does the momentum come from? from the PLC ? it can appear in the period between the PLC requests – then the PLC program requires a delay of this pulse for the network variable. Or did you mean something else ?

    #8502
    AvatarRich Ex
    Participant

    Hi , the single pulse comes from a sensor at the begging of a process line .
    The single pulse only feeds the Scada unit which sends it to the Rapid Scada program.

    Thanks
    Rich

    #8503
    MikhailMikhail
    Moderator

    Hi,
    You need to specify a pulse length and polling rate. And make sure that polling rate is fast enough to detect a pulse.

    #8509
    AvatarRich Ex
    Participant

    Dear Mikhail
    Can you give me some more detail please .
    My pulse is less than 1 second , where do I set up the polling rate ?

    Thank You
    Rich

    #8510
    MikhailMikhail
    Moderator

    Hello,

    where do I set up the polling rate ?

    It’s in Communicator – Communication line – Line Parameters – Request Sequence
    Could you post a part of communication line log here to analyze?

    #8511
    AvatarRich Ex
    Participant

    Hi Mikhail

    Screenshot
    image

    Can you explain the Timeout; Delay; Time ; Period; entries please .

    thanks as always Rich

    #8513
    MikhailMikhail
    Moderator

    Hi,

    Can you explain the Timeout; Delay; Time ; Period; entries please

    Please read this. If something is not clear in the article, ask.

    Could you post a part of communication line log here to analyze? It’s in Line Stats

    #8518
    AvatarRich Ex
    Participant

    Hi MikHail ,
    First , sorry I should have read the document before asking the question about polling times !

    Right here’s the screen shot of the data
    image

    Thanks
    Rich

    #8519
    MikhailMikhail
    Moderator

    Hi,

    According to the log, your polling rate is about 1 second. It depends on network latency and controller speed.
    So you need pulse length at least 2 seconds to detect it stable.

    #8524
    AvatarRich Ex
    Participant

    Hi Mikhail ,

    Yes I’m seeing that now .
    Nothing on the line is happening quickly so I may need to just look at extending the pulse from the sensors ……

    Thank you for your help .
    Rich

    #8532
    AvatarRich Ex
    Participant

    Hi Mikhail ,
    About the scan times , my system is on a VM with a single CPU , this is showing high CPU usage 85-100% , could this be causing my delays ? …… what number of CPU’s would you recommend on a Windows VM machine , I have 9 Scada slaves each giving me 4 inputs .

    Thanks
    Rich

    #8535
    MikhailMikhail
    Moderator

    Hi,

    Could you make a screenshot of the CPU usage by processes (Task Manager)?

    #8537
    AvatarRich Ex
    Participant

    Hi Mikhail ,
    Screens shots of the resource manager of the VM .
    Sorted for highest CPU usage .

    image

    and

    image

    Thanks

    Rich

    #8544
    MikhailMikhail
    Moderator

    Hi,

    What you can do to decrease CPU load:
    1. Use RAM disk for C:\SCADA\ScadaComm\Log directory.
    2. Add this log directory to antivirus exception.
    3. Increase delays after request in request sequence or after line cycle.

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