Measuring, signalling and control devices and instruments for use in machines for the cement, lime, gypsum, ceramic, refractory, metallurgical and chemical industry, for the mining and power industry, namely, monitoring devices for determining levels of wear on roller mills and grinding rollers; computer programs for monitoring and signaling levels of wear on machines used in the cement, lime, gypsum, ceramic, refractory, metallurgical and chemical industry, for the mining and power industry