1.Application

DDSY5558 is a new type of keypad prepayment meter. Customer purchases energy by the vending network to get a serial number (named as "TOKEN"), and then use the keypad of meter to enter the TOKEN. The credit data will be entered into the meter after the TOKEN being accepted. The TOKEN contains 20 digits and is encrypted. For the purchasing method reason, the meter also named as "Keypad meter”. It complies with open standard STS.

2.Feature

Payment by 20 digits token

Alarm when low energy/overload/fraud.

With RS485 and optical communication functions for reading meter and setting parameters.

Open terminal cover detection alarm.

3.Technical parameters

4.Function

4.1 Energy Measure

Bidirectional active energy measurement, reverse energy accumulated to positive energy. Pulse led and pulse terminal output.

The meter can record the remaining energy and accumulative energy. The operator can check the present accumulative energy. The relay will switch off automatically when the remaining energy is less than 0. Only when the remaining energy is more than 0, the relay will be switch on automatically.

4.2 Charge energy

The operator can use the STS encryption techniques and key to input 20digits cryptograph to recharge deposit Energy to remaining energy. The meter will display “ACCEP”.

If the recharge energy amount plus remaining energy more than limited value (9,999,999.99kWh), then the recharge energy will be refused, but the energy amount token is still valid and the token can be used when total energy (the remaining energy plus the charge energy) less that the limited value. The meter will display “REJECT”.

The meter will check whether the time mark of token is already used or not. One meter can only generate one charge token in one minute. The meter will refuse the TOKEN that generated at the same minute and will show “REJECT”.

The meter can check the generated time of the token and record the token used time of the last 50 times. If the generated time of the token is early than the last 50 times, the token will refuse the token and show “REJECT”

4.3 Anti-tamper alarm

Anti-tamper:

The electronic energy meter will alarm when the tampering happened (for example: reverse wiring, open cover). When the upper cover and terminal cover are opened, the alarm will keep on until inputting command of clearing the tampering status even if the cover is closed. Other tampering status will disappear, when the tampering is end.

In the reparation, “Token” means only when input the reparation token we can clean the tampering status. “Repair” means when the tampering is end the tampering status will end.