You may try using a different controller. The PID controller in the standard library and one of the n-stage differential controllers in the TESS Controls Library come to mind. And definitely use smaller timesteps - we prefer a 1-minute timestep for most applications.
Jeff
---
Jeff Thornton President - TESS LLC 22 N. Carroll Street, Madison WI USA 53703 Office: (608) 274-2577 Fax: (608) 278-1475 www.tess-inc.com E-Mail: thornton@tess-inc.com
On 11/26/2014 3:37 pm, bridjesh gautam wrote:
Thank you MR. Heymer and ThrontonI connected control function directly to Type 46 and worked well but I do have one more question.I am controlling Type 110 pump with Type 22 controller and have noticed pump always starts with a peak of rated volume flow. My pump has minimum flow ,25% of rated mass flow and setting minimum control function to 0.25 or even 0 does not help.I tried changing Threshold for non-zero output and Maximum number of oscillations to various value still having no luck.I read that pump does not model on-off condition does that mean running simulation with very small time steps(>1 min) will have bigger impact on overall result ? What can be done so pump does not always start at the peak?Thank you in advance
On Wed, Nov 26, 2014 at 10:16 PM, <trnsys-users-request@lists.onebuilding.org> wrote:
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Today's Topics:
1. Re: On off time calculator type 980 (Jeff Thornton)
---------- Forwarded message ----------
From: Jeff Thornton <thornton@tess-inc.com>
To: "TRNSYS users mailing list at OneBuilding.org" <trnsys-users@lists.onebuilding.org>
Cc: "TRNSYS users mailing list at OneBuilding.org" <trnsys-users@lists.onebuilding.org>
Date: Wed, 26 Nov 2014 09:22:35 -0600
Subject: Re: [TRNSYS-users] On off time calculator type 980
Type 24 already accounts for the time step. As Ben suggests, simply connect the same control signal that you use to drive the pump to an integrator as well.
Jeff Thornton
TESS
Sent from my iPhone
> On Nov 26, 2014, at 8:31 AM, Ben Heymer <bheymer@gmail.com> wrote:
>
> You could integrate the control signal to the pump (should be 0 to 1)
> or build your own simple counter using an equation and an integrator,
> such as type 24, based on some output value from the pump. For
> example:
>
> gt(pump_flow_rate,0) * timestep --> integrator
>
> Type 24 may already account for the time step, you will have to check.
>
> Cheers,
> Ben Heymer, PE
>
> On Wed, Nov 26, 2014 at 4:07 AM, bridjesh gautam
> <bridjeshgautam@gmail.com> wrote:
>> Dear. Trnsys users
>> I need to find out how many hours my pump was on in the simulation. I found
>> type 980 can give me the current running on and off time but not the total
>> ,as it starts from zero next time it is on or off. Is there any other way to
>> find that out ?
>>
>> Thank you
>>
>>
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bridjesh
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