Re: [EnergyPlus_Support] FindRootSimpleController Sever errors

["Karen Walkerman kwalkerman@xxxxxxxxx [EnergyPlus_Support]" <EnergyPlus_Support@xxxxxxxxxxxxxxx>]

I reported a similar issue to the helpdesk in 2013.  This was their response:

"The fix is to change all of your controller "Minimum Actuated Flow" fields to 0.0 and this file will run to completion. Non-zero min flow rates are not well supported and can cause issues. I generally set those to zero (everywhere they are available). That said, this should not cause a fatal error - we will try to sort that out "

What version of EnergyPlus are you using?  This may have been fixed.

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Karen 

On Mon, Jul 11, 2016 at 12:34 PM rajeevkamal@xxxxxxxxx [EnergyPlus_Support] <EnergyPlus_Support@xxxxxxxxxxxxxxx> wrote:

 

One of idf model I am working is showing me the Controller error as bellow for all the VAV Cooling coil controller

** Severe  ** FindRootSimpleController: Controller error for controller = "VAV_1_COOLC_CONTROLLER"

   **   ~~~   **  Environment=ANNUAL, at Simulation time=01/27 18:40 - 18:50

   **   ~~~   **   Controller function is inconsistent with user specified controller action = "" action

   **   ~~~   **   Actuator will be set to maximum action

   **   ~~~   ** Controller control type=Temperature

   **   ~~~   ** Controller temperature setpoint = 12.40 [C]

   **   ~~~   ** Controller sensed temperature = 16.65 [C]

   **   ~~~   ** Controller actuator mass flow rate set to 10.87 [kg/s]

   **   ~~~   ** Controller actuator temperature = 16.67 [C]

   **   ~~~   **   Note: Chilled water coils should be reverse action and the entering chilled

   **   ~~~   **         water temperature (controller actuator temperature) should be below the setpoint temperature

   **   ~~~   **   Note: Hot water coils should be normal action and the entering hot

   **   ~~~   **         water temperature (controller actuator temperature) should be above the setpoint temperature

I have set the ChilledWater coils to reverse action and my Controller is using setpointmanager as

SetpointManager:MixedAir,

    VAV_1_CoolC SAT Manager, !- Name

    Temperature,             !- Control Variable

    VAV_1 Supply Equipment Outlet Node,  !- Reference Setpoint Node Name

    VAV_1_HeatC-VAV_1_FanNode,  !- Fan Inlet Node Name

    VAV_1 Supply Equipment Outlet Node,  !- Fan Outlet Node Name

    VAV_1_CoolC-VAV_1_HeatCNode;  !- Setpoint Node or NodeList Name

*************  ** Severe  ** FindRootSimpleController: Previous controller action error continues for controller = VAV_1_COOLC_CONTROLLER

   *************  **   ~~~   **   This error occurred 11 total times;

   *************  **   ~~~   **   during Warmup 0 times;

   *************  **   ~~~   **   during Sizing 0 times.

I get 48 of these warnings with year of simulation. Can this be ignored safely considering only 12 times in a year for each controller.

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Posted by: Karen Walkerman <kwalkerman@xxxxxxxxx>

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