Functions and characteristics 1. Measure single phase AC active power accurately. 2. Prepayment with IC card, purchasing before using. 3. When the available credit is not enough, a red alarming lamp will keep blinking; when the available credit is half of alarming credit, the meter will turn off automatically, at this time, put the vending-card into the meter, it will turn on at once till the available credit is empty. 4. The meter will turn off automatically when overload. 5. The administrator can copy all meter info real time using the copy-card, in order to check whether the meter is going well. 6. LCD displays the available credit, total consumption, and the opening cover times in turn with 4 integral digits and 2 decimal digits. 7. Outfit the transfer-card, the clear-card and the copy-card to the management station. 8. If the phase and neutral is reversed, the power energy still is measured in same direction. 9. With the tamperproof cover of junction box, the meter can arrest short circuit at the bottom of junction box. If the cover of junction box is opened, the meter will record the opening times automatically, the LCD will show ?C---1?. If the meter is connected incorrectly or creeps in the electrical current loop, the meter will display ?E---1?, at the same time, the digits will run with fast speed and the red alarm lamp will keep blinking.