Flow change resulting in a "server busy" message

<p>Hi all,</p><p>We have a problem with "server busy"-messages. This problem occurs with a system consisting of a Waters Alliance e2695 and a PDA2998. Both are connected via a switch (TCP/IP) to a LACE. No other system ist connected to this LACE. We use Empower 2 FR5. When changing the flow in Run Samples a "servy busy" -message pops up. At this time the system has no other task. The flow is on a low level. Directly confirming the message results in a freeze or crash of the Empower application on the used client. If the message is confirmed only after a few minutes flow can now be changed and no crash of the application happens. This happens every time, no matter which client was used for access. Does anyone know the source of this issue ?</p><p></p><p>Kind regards


  • Hello,

    “Server busy” can be an indicator of many things among those being communications, the server being too busy to acknowledge the request, service not running, etc.

    It is possible that the issue is local to the system.  What flow changes are being made at the time and the steps (clicks) performed?  Are they always the same? Is the stroke volume acceptable for the new flow rate?

    Best regards


  • Hello Dot,

    The steps performed are the same every time:

    - in Run Samples window "Change Flow" is clicked

    - in Change Flow dialog box percentages of flow gradients for the different solvents are specified (if neccassary)

    - Pressure limits are not changed (Low 0,00 ... High 5000,0)

    - then Ramp For is choosen, values are set

    Values for ramping vary around 5 - 7 minutes and ramping from 0,05 up to 0,8 - 1,25 (ml/min). The stroke volume is checked and is acceptable for the new flow rate.

    The steps performed are the same as for two other systems consisting each of a 2695 Alliance and a 2998 PDA. There we have no issue with "server busy". For these systems both Alliances are connected to the same LAC/E via IEEE. The detectors are connected to the LAC/E via an Ethernet-Switch. In contrast on our "busy" system both Alliance and PDA are connected via an Ethernet-Switch to its own LACE (no other system at this LAC/E).

    Best regards


  • Hello

    Since both instruments in this system are Ethernet, can we verify there is no inject start cable attached?  This can throw off timing.

    Also have you tried using a gradient table?

    We can try a test similar test for you.


  • Hello Dot,

    There was a start cable attached (but at "switch" pins at the Alliance). We have tested the connection without any start cable and got the same issue. We also used another network adapter - same issue. We have also tested a configuration with two bridged network adapters - same issue. And we also used another LACE - same issue. At the moment we have the Alliance via IEEE connected. This configuration seems to be ok (as it is for our other systems).
    We use gradient tables in the Instrument methods during Sample Set. For this we have no problems. The steps I've described before are a common procedure to adjust the flow before starting a Sample Set.
    The connection of Alliance and detector via ethernet is not described in the device manuals. Was this configuration tested by Waters? Can you do some tests?

    Best regards