External smart upgrade for conventional LV switches | Panel mounting
External smart upgrade for conventional LV switches | Panel mounting
The MS-LTU(Q) Smart Line Terminal Unit uses panel mounting for smart upgrades to conventional LV switches and distribution circuits. It combines electrical measurement, energy metering, power quality analysis, fault monitoring, event recording, communications and control as a front-end acquisition and monitoring unit for LV distribution.

Monitors voltage, current, power, power factor, frequency, energy and demand.
Monitors 2nd–31st harmonics, total harmonic distortion, three-phase unbalance, voltage and frequency deviation and voltage compliance.
Detects loss of voltage, undervoltage, overvoltage, phase loss, loss of current, current interruption, overload, reverse power flow, reverse phase sequence and neutral loss, and provides three-stage overcurrent protection.
Monitors residual current, temperature and DI status, and records voltage trends, SOE events, maximum/minimum values and fault waveforms.
Supports RS-485 communications and DI/DO input and output for data upload, status acquisition and related control.

| Key Parameters | Technical data |
|---|---|
| Model | MS-LTU(Q) |
| Mounting | Panel mounting |
| Wiring | Three-phase three-wire / three-phase four-wire |
| Rated voltage | 57.7/100V、220/380V、380/660V |
| Voltage/current measurement | True RMS; accuracy class 0.2 |
| Current input | 0.1 A, 1 A or 5 A; 0.1 A input supports external 250 A/400 A/630 A/800 A current transformers |
| Residual-current measurement range | 20mA~2A |
| Communications | 2 RS-485 ports by default; supports DL/T 645 and Modbus |
| Inputs/outputs | 2 DI and 2 DO by default |
| Temperature measurement | 3 NTC inputs, −20 °C to +100 °C, accuracy ±2 °C |
| Operating power supply | AC/DC86~264V |
| Operating temperature | -40°C~+70°C |