[TRNSYS-users] problem about the differential controller (Type2)

[Yin Hang]

Hello,
Thanks for your replying.
I have connected connect the output of the controller to its
"input control function" (input 4).
But if you look at the example in TRNSYS - "DHSW", you will
also find this fluctuation problem.(suddenly on and suddenly
off, even still in the deadband).
Thanks.
Yin

-----Original Message-----
From: Francois Badinier
[mailto:francois.badinier at icax.co.uk]
Sent: Tuesday, September 15, 2009 5:11 AM
To: 'Yin Hang'; trnsys-users at cae.wisc.edu
Subject: RE: [TRNSYS-users] problem about the differential
controller (Type2)

Yin,

Make sure you connect the output of the controller to its
"input control function" (input 4). You link the controller
with itself basically. This has to be done in order to get
the hysteresis effect working (influence of the previous
state).
With that done, it should work properly.

Regards,

François Badinier
Development Engineer
ICAX Ltd
1 Hatfield House
Baltic Street West
London EC1Y OST
francois.badinier at icax.co.uk
www.icax.co.uk




-----Original Message-----
From: Yin Hang [mailto:yhang at purdue.edu]
Sent: 14 September 2009 19:47
To: trnsys-users at cae.wisc.edu
Subject: [TRNSYS-users] problem about the differential
controller (Type2)

Hello,
I have a problem when I use differential controller type2.
For example, I want to control my solar collector loop pump
by using one of this controller.
My control logic is when the outlet temperature of my solar
collector is higher than the inlet temperature of my solar
collector 4C, the pump will be on;
And when it is lower than the inlet temperature for 2C, the
pump will be off.
However, I found the output control signal is fluctuated,
such as it suddenly becomes off even the outlet temperature
is 2C higher than the outlet temperature; and next timestep,
it suddenly on.
Could you help me to fix this problem? I figure it is really
bad since it is un-normal for my pump during true situation.
Thanks.



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