Abstract: A chart recorder has a fixed thermal printhead for recording traces and annotations thereto representative of monitored parameters. A microcomputer, including timing, memory and control circuits controls the operation of the recorder which is enabled to print one or more traces simultaneously. The microcomputer control enables the printing of limit parameters, grids and times along with the traces. Further, the microcomputer provides for linearization of nonlinear parameters to be measured such as thermocouple temperature measurements and the like.