Abstract

A system for measurement and recording of data as to events and conditions is disclosed including a recorder unit adapted to be located at a surveillance site and connected to detectors providing successive signals responsive to successive actuations by individual events, and a portable reader instrument adapted to be connected to said recorder unit. The recorder unit has semi-conductor memory for data and for instructions of a program, and a programmable data processor operable under the control of a program of instructions stored in memory to function in a recording mode. The data processor includes an arithmetic and logic unit for performing computational and decisional processes in a sequence determined by a program to count events in response to the detector signals, and to classify and accumulate the counts as data in separate locations in semi-conductor memory for separate real time periods. The portable reader instrument has a visual display device, a recording device, and a manually operable keyboard and switches for generating display commands and read commands and for transmitting those commands to the recorder unit for reading and displaying data as derived by the data processor of the recorder unit, without interruption of the recording mode, and to display on the visual display and re-record data received from the recorder unit in the recording device of the reader instrument. The reader instrument is employed both for monitoring the operation of the recorder unit and for collecting data recorded in the semi-conductor memory of the recorder unit.