GB/T 21705-2008 Active

This standard applies to general low-voltage electrical appliance power monitors and fieldbus-based power monitors (hereinafter referred to as monitors). The monitors specified in this standard are suitable for circuits with a reference frequency of 50Hz (or 60Hz), and can detect parameters such as voltage, current, active power, reactive power, power factor, frequency, and electrical energy. They can also be equipped with switch input and switch output, and use the switch output to implement certain protection or control functions. They can also be used as monitoring modules in conjunction with low-voltage electrical appliances, enabling low-voltage electrical appliances without intelligent control to have intelligent control and network control functions. This standard does not apply to portable monitors. This standard specifies the classification, working conditions, structural and performance requirements, test methods, and test rules for monitors.