Altivar 21 is a range of frequency inverters for 3-phase asynchronous motors from 0,75 to 75 kW dedicated to building HVAC applications. Compact with an economical design that fits to your needs, it supports all essential functions for variable torque pumps and fans applications (PI regulator, preset PI, automatic restart, recovery with the flight, skip frequencies, belt breakage detection, overload detection and under load detection). The optional built-in card for LonWorks® permits easy integration in a LonWorks network. It complies with the LonMark® Functional Profile for Variable Speed Motor Drives. It provides additional variables that allow extensive control of the inverter (status, measurements, control of the drive relays, values of analog and digital inputs…). The parameters access function enables access to all parameters of the drive.