Program development and analysis of computer operated potentiostat

A potentiostat was designed and built, with modifications incorporated in response to analysis of performance, with the objective of maximizing the capabilities of its operation through real-time computer control with minimum investment in potentiostat hardware. Extensive software was developed for both the operation of the potentiostat and for the analysis of its performance. The 64 Kbyte memory restriction of the PDP-11 computer limited the direct development of large programs. It was demonstrated that the ease of using overlays and chaining facilities provided by the RT-11 operating system permitted the effective use of large programs. The final version of the software consisted of all operating parameters, retaining disk files of parameters, and the storage and/or plotting of generated data.

Performance investigations of the potentiostat/computer combination involved transient response analysis and noise analysis. These analyses included use of a digital memory oscilloscope interfaced to a computer for selection of measurement mode and data analysis. The transient response time of the computer operated potentiostat was 350 microseconds indicating satisfactory performance for a range of potentiostatic measurements. The noise analysis indicated the pickup of noise, either from electromagnetic radiation or through the power lines, was of sufficient magnitude to require improved shielding and power line isolation. Recommendations are made to improve the response time of the system through changes in both the potenstiostat and software.