1408-EM3A-ENT — PowerMonitor 1000 Energy and Demand Meter, EtherNet/IP + RS-485

The 1408-EM3A-ENT is a three-phase power, energy, and demand monitor from the PowerMonitor 1000 family. It measures voltage, current, real power (kW), reactive power (kVAR), apparent power (kVA), true power factor, and energy consumption (kWh) on three-phase or split-phase AC systems. Dual communication interfaces — EtherNet/IP and RS-485 — allow it to report to a PLC, SCADA system, or building management system simultaneously. An integrated LCD display, DIN rail or panel mounting, wiring diagnostics, and onboard data logging round out a meter designed for both standalone monitoring and networked energy management.

Specifications

Parameter	Value
Part Number	1408-EM3A-ENT
Series	PowerMonitor 1000 (EM3)
Measured Parameters	V, A, kW, kVAR, kVA, PF, kWh, demand (projected, actual)
Input Phases	Three-phase or split-phase AC
Voltage Input	Up to 347V L-N / 600V L-L
Current Input	5A (via external CT)
Accuracy	±1%
Control Power	120/240V AC or 125/250V DC (85–264V AC, 47–63 Hz)
EtherNet/IP	Yes — EtherNet/IP (cyclic and explicit), Modbus TCP
RS-485	Yes — DF1 full/half-duplex, Modbus RTU, DH-485
Digital Outputs	2 × relay (configurable)
Display	Integrated LCD
Logging	Energy, min/max, status, load factor, time-of-use logs
Mounting	Panel or 35 mm DIN rail
Operating Temperature	−10°C to 60°C
Standards	UL, CE, cUL, CCC, KC, RCM

What It Measures and Why the Data Matters

Energy and demand are two distinct billing and management metrics. Energy (kWh) is the total power consumed over time — what drives the electricity bill. Demand is the peak average power drawn over a billing period (typically 15 or 30 minutes) — many utilities charge a demand tariff based on peak demand that can represent 30–50% of an industrial electricity bill. The EM3 monitors both, including projected demand (where the current 15-minute window is heading before it closes), which gives operators a real-time signal to curtail non-critical loads before a demand spike is locked in.

Power factor is equally important. Low power factor means more current is drawn from the supply for the same useful work, increasing cable heating and transformer loading. Facilities with induction motor-heavy loads often have power factors below 0.85 — and many utilities impose power factor penalties below a threshold. The EM3 provides continuous power factor visibility, which is the first step to identifying whether correction capacitors or drives are needed to improve the power factor and reduce associated costs.

FAQ

Q: Can the meter measure both EtherNet/IP and RS-485 simultaneously?

Yes. Both communication ports operate independently and simultaneously. A PLC can read real-time power data via EtherNet/IP while a SCADA system polls logged energy data via Modbus RTU over RS-485 at the same time.

Q: What is the difference between EM3 and other PowerMonitor 1000 models?

The EM3 adds demand monitoring (projected and actual demand, load factor, power factor) to the energy measurements in the EM1 and EM2 models. The EM3A-ENT specifically includes both EtherNet/IP and RS-485 communication. Lower-tier models measure energy only; the EM3 is the appropriate choice when demand management or power factor tracking is needed.

Q: Can the meter be used on a single-phase circuit?

The meter supports three-phase and split-phase (2-wire, single-phase) systems. Configure the meter for the circuit topology in the meter's configuration menu. On a single-phase system, only the relevant voltage and current inputs are connected — unused inputs are left open.

Q: How is the integrated web server accessed?

Browse to the meter's IP address from any web browser on the same network. The embedded web page displays real-time measurements and allows parameter configuration without specialized software. DHCP or static IP is configurable in the meter's front-panel menu.

1408-EM3A-ENT New 1408EM3AENT Power Monitor 1000 Power Supply Energy Monitor