Re: [TRNSYS-users] Type 122 -Feedback Controller

["Matt Duffy" <duffy@tess-inc.com>]

Dear Thibaut,

I am not too familiar with the component, but I may be able to offer some
insight. Did you consider the "Special Considerations" section of the
Volume 5 documentation (ref. 5.1.3.3)? "Changing the timestep will have
strong influence on the oscillations." I suggest very carefully adjusting
the timestep and watch the behavior of the controller with the
recommendations that I sent yesterday to Nicola (ref.
https://www-old.cae.wisc.edu/pipermail/trnsys-users/2009/005075.html).

Best regards,

Matt Duffy



----- Original Message -----
From: "Thibaut VITTE" <thibaut.vitte@h3c-energies.fr>
Sent: Thu, September 24, 2009 4:05
Subject:[TRNSYS-users] Type 122 -Feedback Controller

Dear Trnsys Users,

I'm using a feedback controller to control the pump (variable speed) of
the heating loop of a pool.
My timestep is 1 hour, my tolerance on the pool's temperature is 0.25°C
and evrtyhing works fine.
When I try to reduce the timestep to have a more accurate regulation,
the controller stops to works fine. It oscillates a lot (actually all
the time) and doesn't go down to zero. The result is that my water
temperature is greater than the setpoint.
I cannot understantd this behaviour. Is there anything to know for
timesteps with respect to feedback controller?

Thanks in advance.
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----- End of original message -----