A beam diagnostic system which can operate in wide dynamic range of beam currents and energies was developed for REX-ISOLDE. The system generates on-line a two-dimensional beam image and its x and y projections. Features of the system and the technical design are discussed here. Numerous tests were carried out with the system to show that it satisfies the REX-ISOLDE requirements. (C) 2002 Elsevier Science B.V. All rights reserved.