Add-on Manager Help

This page explains what you can do with the Add-on Manager.

Why use Add-on Manager?

DLL files extend CHEMCAD by custom functionality, e.g. unitops, enthalpy models, k value models, pipe models, or kinetic reaction rates.

Add-on Manager can be used to administer your own DLLs – even without downloading a DLL from the shop.

Enjoy these benefits:

  1. Manage many DLLs: CHEMCAD loads only one DLL file, which must be named USRADD.DLL. Add-on Manager can manage (almost) any number of DLL files.
  2. No source code required: Before, CHEMCAD required all functionality in USRADD.DLL, so you had to have access to the source codes of all functionalities and compile them into one USRADD.DLL. This practically inhibited sharing DLLs since intellectual property could not be protected. Add-on Manager loads compiled DLLs.
  3. Mixed language DLLs: In CHEMCAD, USRADD.DLL must be programmed in C++, a programming language which is challenging to master for process engineers. Add-on Manager can load DLLs programmed in many languages, e.g. C++, C#, Java.


Add-on Manager shows a joint list of all dynamic link library (DLL) files in one selected folder of your computer and of all DLLs available in the shop.

It also shows which add-ons you have licensed (e.g. Static Mixer) and where updates are available. Updates are not downloaded automatically, so you stay in control which version you use.

Add-on Manager is a stand-alone program (.EXE file) to administer DLL files. It is installed on your computer.


Add-on Manager currently requires admin rights during installation (this will never change) and updates (which we would really like to change!).

Currently, we are unable to change this behavior because CHEMCAD always looks for the LAB file in the directory in which is located, probably C:\Program Files. We have filed ChIMS issue 6429 on 26 September 2017.

Add-on Manager works with CHEMCAD 7.1 or later only.

Administer your own DLLs

Have you implemented your own CHEMCAD User Added Modules (UAMs)?

If yes, your functions have probably names like ADD1, ADD2, etc. and you have compiled them into USRADD.DLL

Add-on Manager can also administer your UAMs side-by-side with ours after you re-compile your UAMs with a few changes. Contact us at for a short tutorial.