For the precise measurement of the positions of the barrel muon chambers in the CMS detector, a position monitoring system has been developed. Its first functional test in real conditions will be possible for the first time during the CMS magnet test when a significant part of the system will be installed and operated. As the electronics of the barrel muon chambers will not yet be operational, they are substituted by PIConNET units developed for this test. The aim of this paper is to present and discuss the logical organisation, applied tools and methods of setup dedicated to the forthcoming magnet test. I. THE BARREL MUON ALIGNMENT SYSTEM To obtain the required muon momentum resolution in the CMS detector [1] to be built at the Large Hadron Collider (LHC) at CERN (Geneva, Switzerland) the positions of the muon detectors with respect to the central tracker must be known within the 100 to 400 micrometers precision corresponding to the inner to outer chambers respectively. This information is provided by an optical monitoring (also called alignment) system. It consists of four parts: the tracker, barrel muon and end-cap muon internal alignment systems and the link system connecting the other tree parts [2]. The muon barrel alignment system that measures the positions of all the barrel muon chambers (250 altogether) is based on a network of LED light sources, video cameras and rigid mechanical structures (Fig.1).