The short answer in this case is: yes, create an input parameter, connect to a virtual information stream.
The somewhat longer answer: I get the impression that the type of calculation you want to do is some sort of post-processing step that relates to the entire flowsheet solution. To accomplish this, you are inserting unit operations that do parts of your overall calculations. Correct?
A way of dealing with such kind of systems has been proposed (that is, the proposal is undergoing further discussion and approval as official part of the CAPE-OPEN interface standard set in the Method & Tools Special Interest Group, the M&T SIG). This is called flowsheet monitoring. This concept is explained here:
- * http://cocosimulator.org/downloads/AIChE_Philadelphia_2008_ExtendedSummey.pdf
* http://cocosimulator.org/downloads/Flowsheet_Monitoring_Philadelphia_AIChE_2008.pdf
* http://cocosimulator.org/down.php?dl=Sustainability_War_Monitoring_ECCE-8.pdf
* Barrett, W.M., van Baten, J.M. and Martin, T., Implementation of the waste reduction (WAR) algorithm utilizing flowsheet monitoring, Computers and Chemical Engineering 35 (2011) 2680-2686
A prototype of monitoring is available in COFE, and can be used. However, to use it, some programming is required. Let me know if you would like further information on this.