Since version 4.12, an in-line pump can be modeled using a control module. Indeed, a control module is created in this case (with any method adapted to the method that it is desired to use for the variations of the pump discharge, for example the STOP, BOMAT, WDLANG, SCILAB or MATLAB method). At the site of the in-line pump a singular section is placed with a gate-type structure. For this same gate, the opening is declared as control U of the control module, in flow mode (slave controler). See doc on Regulation modules and General settings for U for further details. This solution is probably the best but requires the use of a control module.