Process control in kinetics

Quite a few different set-ups have been demonstrated, in which an irradiation apparatus was combined with different methods of spectroscopy. In all these combinations, process control either by microprocessors or by personal computers, was achieved. Modem instmments contain a microprocessor for process control of the spectrometer and data transfer to a dedicated personal computer. Quite a few years ago data stations were integrated in the spectrometers. However, their flexibility is poor and their software is restricted to the instmmentation making adaptations to user specified problems very difficult. 

In Fig. 4.31 an example is given controlling a dye laser by one microprocessor and a UVA is-spectrometer by another. These two microprocessors are interconnected via data and control lines. Their programs are synchronised. The first microprocessor controls the spectrometer, the second an optical multichannel analyser, which rapidly takes emission spectra during the time the laser pumps the dye solution. Both have to be synchronised with the spectrometer which takes the absorbance spectra. The laser has to be triggered by the optical multichannel analyser. 

the circulating dye solution flashed by the laser can be examined by a vidicon (during the flash) with respect to its laser activity. Using a flow cell with 0.1 mm optical path length because of high absorbance of the dye laser solution, in the spectrometer the photodegradation can be monitored at the same time. Fig. 4.7 gives a view of the cell holder. 

In the case of diode arrays used in applications given in Figs. 4.4, 4.11, 4.12, and 4.28, the overall process control and data handling was programmed in C running on personal computers. In this case the control of 

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