As the time dependence of the calibration constants varies for the different detector types we foresee online calibration per run (approximately every 20 minutes) where needed and in addition calibration in longer intervals.
For the online calibration special data streams will be written to disk buffers and analysed online by the calibration procedure. The data will be written to separate tapes to allow fast recalibration later on. This procedure was applied already at WA89 for vertex detector alignment and lead glass calibration. Calibrations have been performed for time intervals of 20 minutes. This procedure is easily expandable to other detector types.