HOW COMPUTERIZED INSTRUMENTATION MONITORS COAL MINE ROOFS.

The slaved underground data acquisition system consists of a crossbar scanner, six-digit digital voltmeter, programmable coupler-controller, integral clock, digital printer, and paper tape punch. The coupler-controller of the underground unit, has plug-in interface cards that plug into a main frame which allows the user input-output slots for equipment interface. Each component of the data system is coupled through these interface cards and programmed through system control boards. Programs are done in ASCII format code, and several subroutines can be written. These programs allow programming commands to the various components. The entire system has an accuracy of 0. 01%, and will print as well as punch out the data on paper tape indicating the day, hour, and minute the data were taken.