Abstract
DSR E is a system identification algorithm for identification of linear time-invariant systems. DARX is a two-step ARX algorithm which approximates DSR E. The second step of DARX slightly differs from the standard ARX form. Apparently this prevents standard ARX software from being used, requiring a tailor-made implementation of ARX. This paper presents a rewriting of the second step of DARX. Applying this rewriting standard ARX software can be used also for the second step of DARX, simplifying the overall implementation of DARX. The rewriting is validated using timeseries logged at a real-life Czochralski crystallization process.