Industrial evaluation of process control using non-periodic sampling

The main purpose of this work was to further develop and evaluate non-periodic sampling schemes, focusing on their needed communication and the effect they have on the control performance. The paper focuses on evaluating the schemes in experiments on some real industrial processes at Iggesund Paperboard. The industrial evaluation was done using fast wired communication into an ABB AC800M controller with a pre-filtering block mimicking non-periodic communication. The tests show communication reductions of 90 to 99 % compared to the current default sampling intervals in the industry, without significant loss of performance. However, the results further indicate that often carefully selected slower periodic sampling may reduce almost as much communication. In the end the choice of method for communication reduction will be determined by the implementation effort of non-periodic sampling versus the commissioning effort of slow periodic sampling.