To appreciate the importance of CIE 542, we must travel back to the post-World War II industrial boom. Before standardized analog signals, every manufacturer used proprietary signal ranges (e.g., 1-5 V, 0-10 V, 10-50 mA). This created chaos: a Rosemount transmitter could not drive a Honeywell recorder without expensive signal conditioners.
: Being a publication of the CIE, it would carry international weight, influencing standards and practices globally. cie 542