Editing Chart recorder (section)

==Digital chart recorders==
A modern chart recorder is an [[embedded system|embedded computer system]] with an [[analog-to-digital converter]], a [[microcontroller]], and a hard-copy printing device; such instruments allow great flexibility in signal processing, variable chart speed on process upsets, and can also communicate their measurements to remote points.

One of the first digital units was designed by William (Bill) C. McElroy Jr. working for Dohrman Instrument Company in [[Santa Clara, California]]. Up until this unit, most chart recorders were rack mounted and had one speed and one sensitivity range. McElroy's design was an instant loading paper roll 'table-top' unit using an Integrated Chopper Circuit for signal conversion. The unit had plug in circuit boards, plug in single or multi-range modules and plug in single or multi-speed modules. The recorder's sensitivity was 1 microvolt to 100 volts full-scale, which at the time was an industry first. McElroy also aided in the design and build of the Gas Chromatograph used for analysing dirt and rock samples from the 1969 [[Apollo 11]] Moon landing. <ref>William (Bill) C. McElroy jr engineering technician </ref>