Abstract: A multipoint display or recorder system is based upon a digital processor which controls the sampling of data points and the storage of digital values to be displayed or recorded. A digital display device or recorder (e.g. a colummn of LED's or a dot--printing thermal recorder) is controlled by the stored digital values. The processor is capable of determining independent rates for sampling the data points, refreshing the display and effecting read out to the recorder, each rate being matched to the characteristics of the corresponding peripheral (multiplexing sampler and ADC, display device and recorder). The digital processor enables other functions to be performed, e.g. display of alarm levels for the sampled variables and automatic control of the process giving rise to the variables.

Abstract: An improved thermal printing device in which pressure is applied to hold the heat-sensitive paper 5 in contact with a print head 1 by a spring metal comb 8. The comb has a large number of tines (typically 2.5 per millimeter of the comb's width) and can be produced by an etching (or "chemical milling") process. The narrow width of the tines allows very good thermal contact with the print head to be achieved without resort being made to a rubber roller with a high contact pressure. This feature improves uniformity of print and reduces greatly the undesirable effect of the chart paper adhering to the print head through high contact pressure and local heating. The design of the path that the chart paper follows also reduces this undesirable adhering effect. The improved device is very suitable for chart recorders where the paper moves slowly.