NewTrend · programmable single-phase energy metering
Product overview
The DDS238-4 W combines single-phase energy measurement with programmable relay control and electrical protection settings. This two-wire version operates from AC 90–300V and is rated 5(60)A. Choose the local version or the version with RS485 communication. The front LCD and three keys provide access to readings and settings.
Technical selection summary
| Model | DDS238-4 W |
|---|---|
| System | Single-phase two-wire AC; direct connection |
| Working voltage | AC 90–300V |
| Nominal supply references | 120V / 220V / 230V / 240V |
| Rated / maximum current | 5(60)A |
| Minimum measurement current | 20mA |
| Frequency | 50/60Hz |
| Energy accuracy | Class 1 |
| RMS accuracy | Class 0.5 |
| Pulse constant | 1600imp/kWh |
| Display | LCD with SET, up and down keys |
| Energy registers | Bidirectional import and export active energy displayed separately |
| Local functions | Password, energy reset, prepayment, relay timing and countdown |
| Protection settings | Overcurrent, overvoltage, undervoltage and active-power limits |
| Communication option | With RS485 or without RS485 |
| RS485 protocol | MODBUS-RTU; 1200–9600bps, default 9600bps; no parity |
| Dimensions | 93mm high × 76mm wide × 65mm deep |
| Mounting | 35mm DIN rail |
Bidirectional energy and power readings
Imported and exported active energy are measured and displayed separately. The meter also displays real-time active power. Its prepayment mode uses a configurable kWh balance, and the local reset function can clear accumulated energy when required.
Relay timing and protection
Password protection limits access to settings. The programmable relay provides timing and countdown functions; the countdown disconnects the load after the selected number of minutes. Adjustable limits cover overvoltage, undervoltage, overcurrent and active power. Protection and recovery delays are configurable according to the supplied operating sequence.
Local programming sequence
Hold SET for three seconds to enter the setting menu or save and return to the normal display. Use the up key to move between digits and the down key to select a digit or an on/off value. The sequence covers the password, communication address and baud rate on the RS485 version, prepayment enable and recharge, energy reset, countdown and protection thresholds.
RS485 option and terminal arrangement
The RS485 version uses MODBUS-RTU for remote meter reading, programming and supported relay on/off control. Baud rate is selectable from 1200 to 9600bps, with 9600bps and no parity as the defaults. The version without RS485 retains the local display and front-key functions.
The terminal photograph identifies L input, L output, N input and N output, together with the optional communication connector. Match the terminal markings to the chosen version and isolate the supply before wiring or servicing.
Dimensions and DIN-rail mounting
The enclosure measures 93mm high, 76mm wide and 65mm deep. The drawing also identifies a 51mm depth reference and a 45mm front section. Mount the rear clip on a standard 35mm DIN rail and leave room for the terminal covers and front controls.
Typical applications
For residential and commercial submetering, bidirectional energy monitoring, timed load control and distribution-board monitoring. The RS485 version can be integrated into a MODBUS data-collection system.
