NewTrend · three-phase RS485 energy metering
Product overview
The DTS238-4 ZN/S measures three-phase electrical parameters and bidirectional energy. It combines LCD readings, front-panel keys and RS485 communication for local and remote meter reading. Choose 10(100)A direct input or 5A external-CT input, each offered for 3 × 230/400V or 3 × 120/208V systems. The photographs illustrate the direct-connected 100A version.
Technical selection summary
| Model | DTS238-4 ZN/S |
|---|---|
| System | Three-phase four-wire AC |
| Rated voltage options | 3 × 230/400V or 3 × 120/208V |
| Current input options | 10(100)A direct connection or 5A external-CT input |
| External CTs | Purchased separately for the 5A CT version |
| Frequency | 50/60Hz |
| Normal / limit voltage range | 90–110% Un / 70–120% Un |
| Accuracy | Active energy Class 1; reactive energy Class 2; RMS Class 0.5 |
| Measurements | Phase voltage, phase current, active/reactive power, power factor, frequency and energy |
| Energy registers | Total, import and export active energy; total reactive energy; balance energy |
| Communication | RS485, MODBUS-RTU |
| Baud rate | 1200–9600bps; default 9600bps; no parity |
| Remote function | Meter-data reading and supported energy reset via RS485 |
| Pulse indication | LED energy-pulse indication; pulse constant as marked on meter |
| Illustrated 100A pulse constant | 1000imp/kWh |
| Display | LCD with SET, up and down keys |
| Phase indication | A, B and C phase indicators |
| Standard marking | IEC62053-21 on the illustrated unit |
| Mounting | 35mm DIN rail |
| Dimensions | 93 × 76 × 65mm; 51mm depth reference and 45mm front section |
Phase measurements and bidirectional energy
The display provides individual A, B and C phase voltages and currents, phase and total active/reactive power, phase and total power factor, and frequency. Active-energy registers include total, import and export values; the display also provides total reactive energy and balance energy. Reverse energy is included in the total accumulation.
Local display sequence
Use the front keys to step through baud rate b; meter serial-number sections H and L; RS485 address Id; pulse constant C; total/import/export active energy 00/01/02; reactive energy 10; balance energy E; phase voltages UA/Ub/UC; phase currents IA/Ib/IC; active power P/PA/Pb/PC; reactive power q/qA/qb/qC; power factor PF/PFA/PFb/PFC; and frequency F.
RS485 and terminal layout
The MODBUS-RTU interface supports 1200–9600bps with no parity and a default of 9600bps. The RS485 function supports remote reading and the supported command for clearing energy data. The annotated terminal photograph below identifies RS485 A at terminal 19 and B at terminal 20.
Illustrated 100A direct-connected terminal arrangement
| Upper main terminals | A-phase output, B-phase output, C-phase output and neutral output |
|---|---|
| Lower main terminals | A-phase input, B-phase input, C-phase input and neutral input |
| Pulse terminals | 17: P+; 18: P− |
| Communications terminals | 19: RS485 A; 20: RS485 B |
| Front indicators | A/B/C phase indication and energy impulse LED |
The 5A-input version requires external current transformers, supplied separately, and its corresponding CT wiring arrangement. The 120/208V version also supports the stated two-phase three-wire application. Use the wiring arrangement for the selected version.
DIN-rail installation
The rear clip mounts the meter on a 35mm DIN rail. Leave access to the main and communication terminals and the front keys. Isolate the circuit before installing or servicing the wiring.
Dimensions
The enclosure drawing gives 93mm height, 76mm width and 65mm overall depth. The drawing also shows a 51mm depth reference, a 35mm rail section and a 45mm front section.
Typical applications
For commercial, residential and industrial three-phase submetering, electrical-parameter monitoring and RS485 data collection. Select the supply voltage and direct or CT input for the circuit, and coordinate installation protection with the equipment and wiring.
