This publication continues a series of papers devoted to the description of the system and functional software of the package of applied programs REACTOR. A machine independent version of the program monitor is presented. This monitor supports automatic execution of a dynamic chain of program modules. Described ideas and procedures can serve as a basis for the operation of a program package of a big number of separate modules. Source codes of the monitor are written in standard C and Fortran-77. No language mixture, non-standard tools or features are used. In this sense the program monitor is machine independent.