LUMEL ND31PLUS Power Network Meter
With Ethernet Daisy Chain and MQTT (IIoT), BACnet/IP or Modbus TCP/IP Protocols
FEATURES
- Measurement of 54 power network parameters, including current and voltage harmonics up to 63rd in 1-phase 2-wire or 3-phase 3 or 4-wire balanced and unbalanced systems.
- Ethernet Daisy Chain Topology.
- Programmable choice of communication protocols: MQTT, BACnet/IP or MODBUS TCP/IP.
- Modern and user-friendly BACnet/IP interface.
- High accuracy class (0.2S for active energy).
- Graphical color display: LCD 3.5" type TFT, 640 x 480 pixels, fully configurable by a user.
- 14 predefined screens designed for intuitive operation, including harmonics display, analog-style meter visualization, and a demand power screen useful for forecasting power consumption.
- Memory of minimum and maximum values.
- 2 configurable alarm outputs.
- Supervisory relay mode for alarm outputs.
- Analog output 0/4...20 mA for retransmission of the measured value and two Pt 100 inputs (e.g., for measurement of transformer temperature).
- Digital output RS-485 - MODBUS protocol.
- Archiving of up to 32 measured parameters in the internal memory 8 GB.
- Modern and user-friendly Ethernet interface 10/100 BASE-T:
- protocol: MODBUS TCP/IP, HTTP, FTP,
- protocol: MQTT,
- protocol: BACnet/IP,
- services: www server, ftp server, DHCP client, NTP server,
- Daisy Chain communication 2 x RJ45; 10/100 Mbit/s; 10Base-T / 100Base-TX.
- Programming of parameters using free eCon software.
- Overall dimensions: 96 x 96 x 77 mm.
ETHERNET DAISY CHAIN - ONE CABLE, MANY CONNECTIONS
The ND31PLUS is equipped with 2 x RJ45 Ethernet ports that support daisy chain topology — enabling serial connection of Ethernet devices without the need for network switches between them.
What does this mean in practice?
- Saves panel space — no need to install industrial switches,
- Reduces cabling and hardware costs – only one connection between devices,
- Faster installation and fewer errors – simplified wiring,
- Easy system expansion – new devices can be added without modifying the existing infrastructure,
- Improved cabinet organization – fewer cables result in a cleaner setup.
Diagram showing a switch connecting multiple ND31PLUS devices in a daisy chain configuration.
MEASUREMENT AND VISUALIZATION OF POWER NETWORK PARAMETERS
The ND31PLUS measures and visualizes a comprehensive set of power network parameters:
- Phase voltages: U₁, U₂, U₃
- Phase-to-phase voltages: U₁₂, U₂₃, U₃₁
- Phase currents: I₁, I₂, I₃
- Active phase powers: P₁, P₂, P₃
- Reactive phase powers: Q₁, Q₂, Q₃
- Apparent phase powers: S₁, S₂, S₃
- Active power factors: PF₁, PF₂, PF₃
- Reactive/active power factors: tgφ₁, tgφ₂, tgφ₃
- Active, reactive and apparent 3-phase power: P, Q, S
- Mean 3-phase power factors: PF, tgφ
- Frequency f
- Mean 3-phase voltage: U
- Mean phase-to-phase voltage: U₁₂
- Mean 3-phase current: I
- 15, 30, 60 minutes' mean active power: P
demand - Mean apparent power S
demand - Average current I
demand - Active, reactive and apparent 3-phase energy: EnP, EnQ, EnS
- Active, reactive and apparent energy from external counter: EnP
E - Total harmonic content coefficients for phase voltages and currents THD
U1 , THDU2 , THDU3 , THDI1 , THDI2 , THDI3 and for 3-phase voltages and currents THDU , THDI - Harmonics for current and phase voltage up to 63rd!
- Temperature (2 x Pt100 input)
EXAMPLE OF APPLICATION
GLOBAL/DISTRIBUTED MONITORING: Collecting data from production lines to the cloud, enabling parameter monitoring from anywhere in the world and remote decision-making.
LOCAL MONITORING: Calculation of line operating times and performance of energy consumption accounts. Optimization of the production lines through parameter analysis.
Diagram illustrating a distributed monitoring system with ND31PLUS meters connected via Ethernet and RS-485 to a Promotic SCADA system for power guard function, showing data flow from SMT lines to cloud-based monitoring and local analysis.
TECHNICAL DATA
MEASURING RANGE
| Measured value | Measuring range | L1 | L2 | L3 | Σ | Class |
|---|---|---|---|---|---|---|
| Current 1/5 A | 0.002..0.100..1.200 A 0.010..0.500.. 6.000 A ...100.00 kA (tr_I≠1) |
• | • | • | • | 0.2 (EN 61557-12) |
| Voltage L-N 57.7V~ 110V~ 230 V~ 400 V~ |
5.700..11.500..70.000 V 11.000..22.000..132.000 V 23.000..46.000 .. 276.000 V 40.000..80.000.. 480.000 V ...1920.0 kV |
• | • | • | • | 0.2 (EN 61557-12) |
| Voltage L-L 100V~ 190 V~ 400 V~ 690 V~ |
10.000..20.000..120.000 V 19.000..38.000..228.000 V 40.000..80.000.. 480.000 V 69.000..138.000.. 830.000 V ...1999.0 kV (tr_U≠1) |
• | • | • | • | 0.5 (EN 61557-12) |
| Active power P | -19999 MW..0,000 W .. ..19999 MW (tr_U≠1,tr_I≠1) | • | • | • | • | 0.5 (EN 61557-12) |
| Reactive power Q | -19999 MVar.. 0,000 Var .. ..19999 MVar (tr_U≠1,tr_I≠1) | • | • | • | • | 1 (EN 61557-12) |
| Apparent power S | 0.000 .. 1999,9 VA .. ..19999 MVA (tr_U≠1,tr_I≠1) | • | • | • | • | 0.5 (EN 61557-12) |
| Active energy EnP (imported or exported) | 0.000.. 99 999 999.999 kWh | • | • | • | • | 0.25 (EN 62053-22) |
| Reactive energy EnQ (inductive or capacitive) | 0.000 .. 99 999 999.999 kVarh | • | • | • | • | 1 (EN 61557-12) |
| Apparent energy EnS | 0.000.. 99 999 999.999 kVAh | • | • | • | • | 0.5 (EN 61557-12) |
| Active power factor PF | -1.00..0..1.00 | • | • | • | • | 1 (EN 61557-12) |
| Coefficient tgφ (ratio of reactive power to active power) | -999.99...-1.20.. 0 .. 1.20...999.99 | • | • | • | • | 5 (EN 61557-12) |
| Frequency f | 45.00...65.000...100.00 Hz | • | • | • | • | II (IEC61000-4-7) |
| Total harmonic distortion of voltage THDU and current THDI | 0.0..100.0% | • | • | • | • | 5 (EN 61557-12) |
| Amplitudes of the voltage U |
0.0..100.0% | • | • | • | • | II (IEC61000-4-7) |
tr_I - Current transformer ratio = Transformer primary current / Current transformer secondary current
tr_U - Voltage transformer ratio = Transformer primary voltage / Voltage transformer secondary voltage
ADDITIONAL INPUTS
| Input type | Properties |
|---|---|
| Input Pt100 (T1, T2) | 2 x Pt100, 2-wire, measuring range -50...400°C, basic error 0.5% |
DIGITAL INTERFACE
| Interface type | Transmission protocol | Remarks |
|---|---|---|
| Modbus TCP, HTTP, FTP | WWW server, FTP server, DHCP client, NTP server | |
| MQTT | ||
| Ethernet Daisy Chain (2 x RJ45) Ethernet 10/100 Base-T |
BACnet/IP | BACnet Standardized Device Profile (Annex L): BACnet Application Specific Controller (B-ASC); BACnet Interoperability Building Blocks (BIBB) Support (Annex K in BACnet Addendum 135d): DS-RP-B, DS-WP-B, DS-RPM-B, DM-DDB-B, DM-DOB-B, DM-DCC-B, DM-RD-B; Binding methods support: Receive Who-Is, send I-Am (BIBB, DM-DDB-B); Receive Who-Has, send I-Have (BIBB DM-DOB-B) |
| RS-485 | Modbus RTU 8N2,8E1,801,8N1 Address 1..247 baud rate: 4.8, 9.6, 19.2 38.4, 57.6, 115.2 kbit/s |
EXTERNAL FEATURES
| Readout field | graphic color display LCD TFT 3,5", 640 x 480 pixels | mounting hole 92.5 x 92.5 mm |
| Overall dimensions | 96 x 96 x 77 mm | |
| Weight | 0.3 kg | |
| Protection grade | from frontal side: IP65 | from terminal side: IP20 |
RATED OPERATING CONDITIONS
in voltage circuit ≤ 0.5 VA| Supply voltage | 85...253 V a.c. (40...50...400 Hz), 90...300 V d.c. or 20...40 V a.c., 20...60 V d.c. |
power consumption ≤ 6 VA |
| Power consumption | in current circuit ≤ 0.1 VA | |
| Input signal | 0...0.1...1.2 In; 0.1...0.2...1.2 Un for current, voltage, PF₁, tgφ frequency 45...50...60...100 Hz, sinusoidal (THD ≤ 8%) |
|
| Power factor | -1...0...1 | |
| Preheating time | 5 min. | |
| Ambient temperature | -10...23...55°C, class K55 acc. to EN61557-12 | without condensation |
| Humidity | 0...40...60...95% | |
| Operating position | any | |
| External magnetic field | ≤40...400 A/m d.c. | ≤ 3 A/m a.c. 50/60 Hz |
| Short-term overload | voltage input: 2 Un (5 sec.) | current input 50 A (1 sec.) |
| Admissible crest factor | current: 2 | |
| Additional error (in % of the intrinsic error) | from ambient temperature change: < 50% / 10°C |
SAFETY AND COMPATIBILITY REQUIREMENTS
| Electromagnetic compatibility | noise immunity radio-frequency common mode: level 2: 0,15...1 MHz level 3: 1 MHz...80 MHz noise emissions |
acc. to EN 61000-6-2, EN IEC 61326-1 acc. to EN 61000-6-4, EN IEC 61326-1 |
| Isolation between circuits | basic for supply circuit and relay outputs 300 V for measuring input 500 V for circuits of RS-485, Ethernet, analog outputs: 50 V |
acc. to EN 61010-1 acc. to EN 61010-1 acc. to EN 61010-1 |
| Polution level | 2 | |
| Overvoltage category OVC | III | II |
| Maximal phase-to-earth voltage | for voltage to earth up to 300V | for voltage to earth up to 600V |
Altitude a.s.l.
≤ 2000 m
CONNECTION DIAGRAMS
Diagram showing connection terminals for ND31PLUS, including power, measurement, communication (RS485, Ethernet), and analog/digital I/O.
Diagram illustrating indirect measurement in a 4-wire network, showing connection of input signals.
DISPLAING OF MEASUREMENT PARAMETERS
The ND31PLUS offers various display screens for measurement parameters:
- Main Screen: Displays key parameters like voltages (U1, U2, U3), currents (I1, I2, I3), frequency (Hz), and average current (I avg).
- Energy Screens: Show accumulated active energy (En P+), reactive energy (En Q), and apparent energy (En S) in various units (kWh, kVarh, kVAh).
- Harmonics Screens: Provide detailed harmonic analysis for voltages and currents, including individual harmonic levels and bar graph representations up to the 51st harmonic.
- Analog Meter View: Displays parameters in an analog meter format with min/max preview and zoom functionality.
- Contracted Power Representation: Shows Max Demand in W, kW, or MW, useful for power consumption forecasting.
Screenshots of the ND31PLUS display showing different measurement parameter views, including main parameters, energy values, harmonic analysis, analog meter style, and power demand.
METER CONFIGURATION WITH FREE ECON SOFTWARE
The ND31PLUS can be configured and updated using the free eCon software via RS-485 or Ethernet interface. The software provides an intuitive menu for setting parameters, alarms, analog outputs, display, archiving, and communication protocols.
Screenshot of the eCon software interface showing meter configuration options for ND31PLUS.
REMOTE READOUT OF PARAMETERS THROUGH ETHERNET: WWW SERVER, FTP
The built-in WEB server allows for remote reading of current measurement data, while the FTP server enables downloading of archived CSV files.
Screenshots showing the WEB interface for remote data access and a table displaying various measured parameters.
ORDERING CODE
The ordering code specifies the meter's configuration. For example, ND31PLUS-11M0 indicates:
- ND31PLUS - meter model
- 1 - input voltage 3 x 57.7/100 V, 3 x 230/400 V
- 1 - supply 85..253 V a.c., 90..300 V d.c.
- M - Polish-English version
- 0 - standard version, without additional quality requirements
Table detailing the options for input voltage, supply, language, acceptance tests, and version for constructing the ordering code.
