1.1 *Scope This International Standard applies to the basic safety and essential performance of medical electrical equipment and medical electrical systems, hereafter referred to as me equipment and me systems. This collateral standard specifies requirements for the development (analysis, design, verification and validation) of a physiologic closed-loop controller (pclc) as part of a physiologic closed-loop control system (pclcs) to control at least one patient variable (i.e. a physiologic variable) in me equipment and me systems. EXAMPLE A patient variable can be a measure of body chemistry (e.g. electrolytes or blood glucose value), a physical property (e.g. body temperature, electrophysiologic characteristic, hemodynamic quantity), or a pharmaceutical concentration. This collateral standard applies to various types of pclc, e.g. linear and non-linear, adaptive, fuzzy, neural networks. This collateral standard does not specify: additional mechanical requirements; or additional electrical requirements. This collateral standard applies to a closed-loop controller (see Figure1) that sets the controller output variable in order to adjust (i.e., change or maintain) the measured physiologic variable by relating it to the reference variable. A closed-loop controller that maintains a physical or chemical variable, using feedback that is not measured from a patient, is outside the scope of this standard. 1.2 Object The object of this collateral standard is to specify general requirements that are in addition to those of the general standard and to serve as the basis for particular standards. 1.3 Related standards 1.3.1 IEC60601‑1 For me equipment and me systems, this collateral standard complements IEC60601‑1. When referring to IEC60601‑1 or to this collateral standard, either individually or in combination, the following conventions are used: \'the general standard\' designates IEC60601‑1 alone, including any amendments; \'this collateral standard\' designates IEC60601‑1‑10 alone, including any amendments; \'this standard\' designates the combination of the general standard and this collateral standard. 1.3.2 Particular standards A requirement in a particular standard takes priority over the corresponding requirement in this collateral standard.