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Re: [TRNSYS-users] Strange error when using the equation proforma

Chun Kwong,
Internally, TRNSYS replaces functions like MAX(), GT(), LE() with a single letter character. The internal representation of either the GT() function or the MAX() function is probably "j" - thus the strange representation of your equation in the list file. Looking through your equations, I see 

M_ChWS_PSA = gt(N_ahu_PSA1,0.1) ...

but I don't see an equation that sets the value of N_ahu_PSA1. If that variable is an input to your Trnsys Studio equation block then make sure that you have the output of an equation connected up to it. If N_ahu_PSA1 is the result of another equation, open up your *.dck file and search through it to make sure that the equation is correctly defined elsewhere in the input file.
Kind regards,
 David



On 2/14/2011 08:34, Matt Duffy wrote:

Dear Chun Kwong LEE,

This is very strange. I wonder if it is similar to what David Bradley
wrote to the group last week about special characters? What TRNSYS version
are you using?

Best regards,

Matt Duffy


----- Original Message -----
From: ""<a8304506@graduate.hku.hk>
Sent: Mon, February 14, 2011 3:01
Subject:[TRNSYS-users] Strange error when using the equation proforma


Dear Trnsys users.

When I try to simulate a HVAC system, I got the following error message
copied
from the .lst file related to an equation proforma:


* EQUATIONS "ChWSH_P"


   EQUATIONS  12
      M_ChWS_PO_max = 85323
      M_ChWS_PSA_max = 104280
      S_SAV_PO1 = gt([71,1],0.1)*gt([86,1],0.01)*Max(Min([86,1],1.0),0.3)
      S_SAV_PSA1 = gt([71,5],0.01)*gt([110,1],0.01)*Max(Min([110,1],1.0),0.3)
      tMP = M_ChWS_PO_max*S_SAV_PO1+M_ChWS_PSA_max*S_SAV_PSA1
      xPO = gt(tMP,0.01)*M_ChWS_PO_max*S_SAV_PO1/Max(tMP,0.01)
      xPSA = 1-xPO
      M_ChWS_PO =
gt(N_ahu_PO,0.1)*Min([43,2]*N_chwsp_P*S_SAV_PO1,M_ChWS_PO_max)/Max(N_ahu_PO,0.01)
      M_ChWS_PSA =
gt(N_ahu_PSA1,0.1)*Min([43,2]*N_chwsp_P*S_SAV_PSA1,M_ChWS_PSA_max)/Max(N_ahu_PSA1,0.01)

*** Fatal Error at time   :         0.000000
     Generated by Unit     : Not applicable or not available
     Generated by Type     : Not applicable or not available
     TRNSYS Message     20 : The referenced variable used in this equation has
not been defined in the TRNSYS input file. The equation begins with the
string
in "reported information"
     Reported information  : M_CHWS_PSA =  j(N_AH


*** Fatal Error at time   :         0.000000
     Generated by Unit     : Not applicable or not available
     Generated by Type     : Not applicable or not available
     TRNSYS Message     20 : The referenced variable used in this equation has
not been defined in the TRNSYS input file. The equation begins with the
string
in "reported information"
     Reported information  : M_CHWS_PSA =  j(N_AH

Does anyone konw what's going wrong?  Another strange matter is that when I
input the formula for M_ChWS_PO, I use N_ahu_PO1 (see attached screenshot).
However, in the input and listing files, it becomes N_ahu_PO.  How can I
rectify
the problem?  Thank you!

Best Regards
LEE, Chun Kwong
City University of Hong Kong

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----- End of original message -----

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--
***************************
David BRADLEY
Principal
Thermal Energy Systems Specialists, LLC
22 North Carroll Street - suite 370
Madison, WI  53703 USA

P:+1.608.274.2577
F:+1.608.278.1475
d.bradley@tess-inc.com

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