Energy consumption monitoring over modbus RTU RS485

Prepaid Energy Meter with Modbus RS485 — Single Phase and Three Phase

The SEMSPMEP is a prepaid energy meter with Modbus RS485 output, available in single-phase and three-phase versions. It measures energy consumption, enforces a credit-based power cutoff via a built-in relay, and is available with multiple connectivity options — Modbus only, Modbus + WiFi, or Modbus + WiFi + LoRa.

How Prepaid Metering Works

The meter tracks cumulative energy consumption per tenant or load. When the prepaid credit balance runs out, the built-in relay cuts off supply to that load. Credit is topped up through the connected platform — via a management app, cloud portal, or token issued by the landlord or administrator. This eliminates unpaid bills and manual disconnection visits.

Variant Selection Guide

1. CT Type

• Built-in CT — compact installation; CT is internal to the meter unit. Suitable for lower current loads.
• External CT — for higher current loads; the current transformer clamps around the existing cable externally. No need to break the live conductor.

2. Phase

• Single Phase (SP) — residential flats, small shops, single-phase commercial loads
• Three Phase (TP) — industrial connections, large commercial premises, 3-phase machinery

3. Connectivity

• Modbus only — RS485 Modbus RTU output; connect to any Modbus master (PLC, SCADA, existing BMS)
• Modbus + WiFi — RS485 output plus direct WiFi cloud connectivity; no separate gateway needed for internet access
• Modbus + WiFi + LoRa — full connectivity stack; use Modbus locally and LoRa for long-range or building-wide aggregation via Ahoy gateways

Use Cases

• Tenant sub-metering — apartment buildings, PGs, co-working spaces, serviced offices; charge tenants for actual consumption with automatic credit enforcement
• Industrial plots and sheds — meter individual units or machines; prepaid credit prevents unpaid usage
• Construction sites — temporary power metering with remote disconnection when contract ends
• Common area metering — hotels, hostels, hospitals; monitor and control energy per zone or floor

Key Specifications

• Metering output: kWh, voltage, current, power factor, frequency
• Output protocol: Modbus RS485 RTU (all variants)
• Connectivity options: Modbus only | Modbus + WiFi | Modbus + WiFi + LoRa
• Phase: Single phase (SP) and three phase (TP) available
• CT options: Built-in CT | External CT
• Prepaid enforcement: Built-in relay cuts supply when credit balance reaches zero