Don't hold this against me, but I'm a quantity surveyor!
We use Costx to import IFC models in order to prepare cost plans and bid documents. To date most of our collaboration has been with design teams that use Revit, but recently we have been working with a design team who use Archicad.
Our approach to collaboration is not limited to simply sharing information, it extends to being as dynamic as possible and this is where Costx comes into it's own because once a cost model is set up we can update it quickly to respond to design development, provided we have an IFC model to work from.
When working with Revit models we have a solution for converting rvt files to IFC files that doesn't rely upon the designer doing that for us (https://rvt-to-ifc.bim42.com). This means all they have to do is make sure their rvt files are up to date on the project portal and we can do the rest.
We're looking for a similar solution for Archicad files. We don't need to own a copy of Archicad, or Revit. We're not designers. We only need access to the IFC model and we want to make life for the design team as straight forward to possible, whilst providing them (and the client) with as up to date cost information as possible. The Revit to IFC solution we use has been a god send, and it's affordable. Hopefully someone can steer me in the direction of an Archicad solution that works as equally well.
I have worked with Quantity Surveyors using Costx for many years. And I have also been into their offices here in Brisbane, Australia when Simon Lovegrove still led them, before they were bought out from RIB2.
There is not a workflow available outside of Archicad to convert PLN files into IFC, sorry. But if you are working with Architects using Archicad then I would suggest that you work with them to set up a guidance document that you can use in future collaborations. That guidance document would need to include translator settings and IFC mapping requirements. It may also include specific requirements around the use of Classification Systems and any additional information that you need specifically set for each element in the model.
Another thing you may want to include in a model requirements/responsibility matrix. That way you will know what is modelled and what isn't modelled. So you can then go to a specification to identify and add measures for elements that are not modelled.