# BCVTB coupling error with matlab and Energyplus

Hello everyone, I am trying to carryout a co-simulation of energyplus and matlab through using the BCVTB. But after the simulation starts i got an error. The version of my energyplus is 8.8 and my BCVTB system is modified from the example file of 'ePlus85Simulink-simple' which comes along with BCVTB. In my system the energyplus creates two external interface:shcedule (one is the schedule of outdoor wetbulb temperature and the other is wetbuld temperature) to exchange the data with the matlab. 1 output variables from Energyplus is received by the matlab script and two outputs from the matlab are transferred to energyplus external schedule. The stack trace of the error is shown below: The energyplus simulation log is shown below:

**Update of my question:**
The problem in the above question is already solved. The error described in the above texts was caused by the wrong input arguments in the **exchangeDoublesWithSocket** function which is used in the matlab script to exchange data with the BCVTB. The variable vector as an input argument read by the matlab should be in the left handside of the **exchangeDoublesWithSocket** function, however in my previous version i put this argument in the right hand side.
** However now i got some new concerns about my model**:
In my model, only one output variable from Energyplus (environment: on site air drybuld temperature) is expected to be read by the matlab and i have declared this in the variable.cfg in the energyplus folder. However, when i started running the simulation, the matlab trigger some warning message: two double variables are read by matlab while only one variable is expected.Then the simulation stoped and shows errors.
I donot understand why two variables are read. To look insight this problem, i just difined the vector u (the variable vector read by the Matlab) to be two dimensional and assigned the initial value (u=[20,50]) and then i re-run the model and got no errors. From the results, i find the first the variable written to the vector u is the value of timestep and the second variable is my target value (on site air dry buld temperature). I donot understand why the value of time step was written into the vector u. Please give me some comments if you know the possible causes and i will quite appreciate your help. Thanks a lot!. The links to download my model is in the following:
link text

I can't download your files. Could you resend the link?

Thanks a lot, Thierry. The initial problem i had in this question has been solved, but now i get a new question. i just update my question here and send a new link to download the BCVTB model.