The newest version of indicators (previous PZT-21 to PZT-29) is PZT-30 device. Tap-changer position indicator is designed for remote reading of number of actually chosen tap and for recording operation data of tap-changer. Indicator makes possible sending information about tap position through current output or BCD/digital output and serial interface RS 485 with MODBUS RTU protocol.

Device is composed of transmitter and receiver. Transmitter consists of 27 position rotation switch and coder card, which are coupled mechanically with tap changer. Receiver is installed on substation area information table, on LCD display are shown: actual tap-changer position, total number of switchovers from the moment of position indicator installation, switchover history with direction (up and down), time and data stamp. Indicator shows operation statistics: percentage time of operation on each position.
Indicator enables co-operation with voltage regulator by output interface: current 0 ÷ 20 mA or 0 ÷ 5 mA, or digital: binary or BCD code.
Serial RS 485 interface (MODBUS RTU protocol) enables communication between receiver and SCADA system.