Diagnostic parameters, used to reduce the number of failures of agricultural machinery

The purpose is to clarify the diagnostic parameters of agricultural machinery. Methods. The analysis of science and practice of technical service of MTP since 1925 is carried out. Results. The most widely used indicator of the state of the elements and aggregates of the MTP in the agro-industrial complex is the permissible value of the diagnostic parameter, and the limit value is secondary. And clarifying their rank is relevant. The main optimum for technical service standards is the minimum of total investment costs, known in the agro-industrial complex since the 30s and developed by V.M. Mikhlin. But only the permissible parameters are justified by it. It is abstract, laborious, not correct, practically not implemented, given only to gradual parametric failures, and real failures are beyond attention. The influence of permissible parameters on reliability, technical resource is overestimated. Organoleptic diagnosis, which is relevant in the absence of diagnostic tools, is beyond attention. Conclusions. The resource diagnostic parameters have been clarified: nominal, current, limit values, and permissible values are secondary, relevant only for regulated parameters. The condition of equality of technical service costs with the cost of a new or repaired analogue is suitable for justifying the limit values of the resource parameters. And the standards of regulated parameters should be set constructively