WB-MAP3E

This page describes the latest hardware revision with the latest stable firmware. If your device runs older firmware, update it where possible (see Firmware update).

Split-core current transformers for the meter

Purpose

This energy meter and electrical-network analyser is intended for energy management and power-quality monitoring, including operational submetering in apartment and office buildings and load monitoring in data centres and smart offices. External split-core current transformers allow installation around conductors without interrupting the loads. Accuracy class is 0.5S for active energy and 1 for reactive energy.

Unlike WB-MAP3H, WB-MAP3E measures peak current and voltage over defined intervals. WB-MAP3E does not measure current/voltage harmonic amplitudes or total harmonic distortion.

Technical specifications

WB-MAP measures and calculates electrical-network parameters including:

RMS phase voltages and currents (Urms, Irms);
peak phase currents and voltages. Detectable peak duration starts at 300 µs and is determined by input filtering. Two sets of registers are available:
- instantaneous peaks — maximum over the detection interval, 20 ms by default;
- aggregated peaks — maximum over the aggregation interval, 60 s by default.
line-to-line voltages for three-phase loads;
active, reactive, apparent and non-active power;
power factor;
forward and reverse active, reactive, apparent and non-active energy;
total power and energy for three-phase loads;
phase angle between voltage and current;
frequency.

RMS and peak currents and voltages, power, power factor, phase angles and frequency are sampled several thousand times per voltage cycle, averaged over 16 cycles and updated in registers every 320 ms. Energy registers are updated as energy is accumulated.

For the full parameter list, see WB-MAP measured parameters, errors and web-interface names. Supported parameters depend on the meter variant; not every listed parameter is available on every model.

Accuracy class is 0.5S for active power and energy and 1 for reactive power and energy.
Relative measurement errors depend on the measured value and load type. See WB-MAP accuracy classes and measurement errors.

Registered as a measuring instrument under State Register number 79082-20. Metrological and technical characteristics are given in the type description.

Technical specifications

Parameter	Value
Power supply
Supply voltage	5.5–28 V DC (interface section) 90–510 V AC (measurement section)
Permissible voltage at L1, L2 and L3	1200 V for 10 ms
Maximum power consumption	1.3 W
Average power consumption	0.9 W
Measurement channels
Number of channels	One three-phase circuit
Detectable transient duration for voltage and current	from 300 µs
Maximum measured current	60 mA RMS at the current transformer secondary
Temperature coefficient of current-input resistor resistance	50 ppm
Terminal blocks and wire cross-sections
Recommended wire cross-section with insulated wire-end ferrules	control inputs: 0.35–1 mm² — single ferrule; 0.35–0.5 mm² — twin ferrule, power inputs: up to 2.5 mm² — single ferrule; up to 1.5 mm² — twin ferrule
Standard ferrule sleeve length	8 mm
Screw tightening torque	control inputs: 0.2 N·m, power outputs: 0.5 N·m
Control
Control interface	RS-485
Interface isolation	Galvanically isolated from the measurement circuits
Communication protocol	Modbus RTU; software-configurable address; factory settings are printed on the label
RS-485 interface parameters	Software-configurable; defaults: baud rate — 9600 bit/s; data — 8 bits; parity — none (N); stop bits — 2
Ready after power-on	~2 c
Operating conditions
Ambient air temperature	−40 to +80 °C
Relative humidity	Up to 92%, non-condensing
Climatic classification under GOST 15150-69	O2.1*
Warranty	2 years
Service life	10 years
Dimensions
Width, DIN modules	3
Overall dimensions (L × W × H)	53 × 90 × 58 mm
Weight (including box)	135 g

Operating principle

The device uses Atmel M90E32AS metering ICs with three current and voltage channels.

Each channel measures instantaneous voltage and current and multiplies them to obtain instantaneous power. The filtered product gives power and its integral gives energy. Reactive power is calculated by multiplying instantaneous current by voltage shifted by 90°.

Channels operate independently. Each measurement engine is fixed to its current input, but phase mapping can assign any of the three voltage phases to it.

Three-phase active and reactive power are the sums of the corresponding channel powers. Forward three-phase active and reactive energy are likewise sums of the respective forward channel energies.

Measurement and calculation methods:

Urms Lx (V)— RMS voltage between Lx and N. Conventional billing meters calculate RMS directly; WB-MAP averages over 16 cycles, or every 320 ms.
Upeak Lx inst (V)— peak voltage between Lx and N over the detection interval, 20 ms by default.
Upeak Lx (V)— aggregated peak voltage between Lx and N. Detectable pulses start at 300 µs, as determined by input filters. The aggregation update interval is configurable, default 60 seconds.
U Lx-Ly (V)— line-to-line voltage between Lx and Ly, calculated using the cosine rule. Line-to-line voltage measurement with WB-MAP.
Phase angle Lx (degrees)— voltage/current phase displacement, from 0° to 360°. WB-MAP extracts the fundamental component and detects zero crossings, calculating the angle from their time difference.
Voltage angle Lx (degrees)— voltage phase displacement between phases, from 0° to 360°. L1 is always 0; L2 and L3 are measured relative to L1.
Irms Lx (A)— RMS phase current. Conventional billing meters calculate RMS directly; WB-MAP averages over 16 cycles, or every 320 ms.
Ipeak Lx inst (A)— peak phase current over the detection interval, 20 ms by default.
Ipeak Lx (A)— aggregated peak phase current. Detectable pulses start at 300 µs, as determined by input filters. The aggregation update interval is configurable, default 60 seconds.
P Lx (W)— active power, associated with the energy billed by the electricity supplier. WB-MAP and billing meters calculate it from the instantaneous voltage/current product.
Q Lx (var)— reactive power. The source notes that conventional reactive-power accuracy is specified for linear loads. Some meters display non-active power N as Q, since they coincide for linear loads, sometimes adding a sign according to the voltage/current quadrant. For non-sinusoidal currents, WB-MAP measures fundamental reactive power according to IEC 62053-24 by multiplying current by voltage shifted by 90°.
S Lx (VA)— apparent power, defined and calculated as Irms × Urms. A load with S = 2 kVA heats conductors like a resistive load with P = 2 kW at the same voltage, because the RMS current is the same.
N Lx (var)— non-active power, calculated from N² = S² − P². It represents the component associated with current and conductor heating that does not perform useful work.
PF Lx— power factor, calculated as PF = P/S: the fraction of apparent power corresponding to useful active power.

Measurement circuit isolation

The meter uses a neutral attenuation network: the measurement circuit is attenuated from both phase conductors and neutral. The ADC reference is connected to PE rather than neutral.

Without PE connected, unused phase terminals can acquire a potential determined by the connected phase-voltage vectors and internal divider ratios. For example, with 230 V on one phase, another may sit at approximately 230 × 0.3/1.3 = 53 V.

The optional Detect disconnected phases function sets voltage and associated power readings to zero if that phase voltage is below 30% of the highest phase voltage.

Meter power supply

The meter has two power sources:

phase-voltage supply, absent in some variants; voltage on any one phase is sufficient;
interface-section supply.

Either source can power the measurement section. Modbus communication requires power at the interface terminals V+ and GND.

With no voltage on any phase, only current-transformer RMS current readings remain valid.

Voltage dips and interruptions

Accumulated energy is retained when meter power is removed.

Installation

Connecting WB-MAP3E(H) to a three-phase supply

MAP meter installation instructions

Mount the device on a standard 35 mm DIN rail. The page Installing WB-MAP multichannel meters in a cabinet provides a short installation sequence. Read the detailed steps below before following it.

Wiring the communication interface

The V+ GND A B terminal block, with a 3.5 mm pitch, connects the power supply and RS-485 communication bus. Correct bus wiring is essential for reliable communication; see RS-485 bus wiring and connection.

If devices on the RS-485 bus use different power supplies, their GND terminals must be interconnected. See Grounding Wiren Board devices and connecting GND and iGND.

Wiring the high-voltage section

Always connect PE to protective earth and N to neutral.

Connect three phases, neutral and protective earth to the high-voltage terminal block. Connecting phases through a circuit breaker simplifies installation; choose its rating to suit the wire cross-section.

The PE conductor grounds the CT secondary circuits. Without it, accidental mains contact on one CT cable can put mains potential on all CT cables. With protective earthing connected, the RCD trips or the resistors at the current inputs burn out.

Connect L1 (A), L2 (B) and L3 (C) according to the terminal labels.

For three phases, Voltage angle readings are L1 = 0°, L2 ≈ +120°, L3 ≈ −120°, or 0°/−120°/+120°. Either phase sequence is supported.

Connection to single-phase networks

For single-phase use, connect the phase conductor to L1. L1 readings are valid; vector-sum energy and power (SV) are unavailable.

To use all current inputs, map them to the connected phase; see Phase mapping configuration.

The voltage inputs are high-impedance. Unused Lx inputs may pick up interference that appears as a measured voltage. Connect unused phase inputs to N to prevent this.

Connection to voltage transformer secondary circuits (57 V)

The meter supports instrument voltage-transformer secondaries, for example in 6–110 kV networks with 57.7 V phase-to-neutral and 100 V line-to-line secondary voltage.

Connect the VT secondary phase conductors to L1, L2 and L3, and neutral to N.

Because approximately 57 V is below the 90–510 V phase-supply range, power the meter through the interface section. Phase-derived power is unavailable in this arrangement.

Voltage, power and accumulated energy readings then refer to the VT secondary. Multiply them by the VT ratio to obtain primary-network values.

Connecting current transformers

Fit current transformers around the corresponding phase conductors, with each arrow pointing towards the load:

1 — L1(A), 2 — L2(B), 3 — L3(C).

If a CT was fitted backwards, its polarity can be inverted in the settings.

Connect white/red CT leads to the positive current inputs and black leads to the negative inputs. Do not join connected CT leads together or connect them to other circuits. The meter internally provides protective earthing of CT secondaries to PE.

For a preconfigured/calibrated meter, each CT is individually assigned and labelled for its channel. Connect it to that channel. If a CT is already around an energised conductor but its secondary cannot yet be connected to the meter, short its secondary leads together to prevent core buzzing and heating.

A core gap can also cause buzzing. Check that the core is firmly closed and the secondary leads are not left open.

Extending CT leads

Allow for cable resistance. Total loop resistance must not exceed 4 Ω for KCT/CTSA transformers or 14 Ω for WB-CT309 assemblies; higher resistance reduces accuracy. Keep the two CT leads together, away from power cables, and use shielded cable for extensions.

Standard copper twisted pair with 0.20 mm² conductors has resistance of approximately 10 Ω per 100 m. The source permits extensions up to 10 m for KCT/CTSA and 70 m for WB-CT309 using this cable. For longer runs, use a larger cross-section, for example KGVEV 7×1.0.

Shortening CT leads

Standard leads can be shortened without affecting accuracy or CT operation.

Cleaning the magnetic core

Clean the mating core faces before closing the CT around a conductor.

Fingerprints, dirt and dust create an air gap that reduces accuracy.

Fingerprints and dust on the core reduce measurement accuracy
Clean magnetic core surface

Securing current transformers

Poor mechanical installation can also create a gap between the core halves.

Check that the transformer:

is closed squarely, without misalignment;

can rotate freely around the conductor.

Otherwise, mechanical stress can create an air gap, with measurement error of 10% or more.

The CT should rotate freely around the conductor
Correct fitting: CT rotates freely
Incorrect CT fitting

Current transformer orientation

CT around a phase conductor, with its arrow pointing towards the load. Shown open for illustration.

Software polarity inversion allows a CT to operate in either physical orientation.

Fit each CT in the correct orientation and connect its leads with the correct polarity. For a consuming load, the arrow points along the phase conductor towards the load.

This assumes the circuit consumes energy. Some solar or wind inverters export surplus energy to the grid; externally driven motors can also generate electricity.

Without local generation, correctly oriented CTs give positive active power; reversed CTs give negative active power.

Checking the wiring

To prevent measurement errors, check the connections:

Apply a load of approximately 100 W per phase.
In the controller interface, check:
- the angle between current and voltage — it should be between −40° and +40°.
- active power on the phase — it should be positive.

For predominantly resistive loads such as lighting, heaters and other household appliances, voltage/current phase displacement is normally within a few tens of degrees.

Angles above 100° indicate that the CT is around the wrong phase conductor. This check may not apply to reactive-power compensation equipment or large motors.

Small voltage/current phase angle: L1 CT correctly connected
Large voltage/current phase angle: the measured current belongs to a different phase and the CT is incorrectly assigned

Positive active power: the phase is sufficiently loaded
Voltage/current phase angle below 40°: CTs correctly fitted
Voltage/current phase angle above 40°: L1 and L2 CTs interchanged

Using instrument transformers for high currents

Standard 800/5 A CT: fit WB-MAP CTs around its secondary circuit conductors

WB-MAP current inputs measure up to 60 mA RMS at the CT secondary. A 200 A/100 mA transformer can be connected, but the measurement range is limited to 60/100 × 200 = 120 A.

Never connect a 5 A secondary directly to WB-MAP. Use an intermediate CT, for example KCT-6 or WB-CT309 (a 5 A/25 mA transformer is recommended).

Fit the WB-MAP CT around a conductor in the 5 A secondary circuit. That secondary must remain short-circuited or connected to an existing meter; leaving it open can destroy the transformer.

Scale the readings in software by the additional transformation ratio. For an 800/5 A upstream CT, multiply the WB-MAP reading by 160: to obtain the primary value. Apply the factor to current, power and energy. Alternatively, multiply the CT ratios and write the combined value to the ratio register if it is below 65536; the meter then reports the primary values directly.

Configuration

Example label: transformation ratio 2000; phase correction 1062

Configuration methods

Set the parameters in the Wiren Board controller web interface under Settings → Configs → Serial devices driver configuration. If these items are unavailable, check your access level.
Write settings to the Modbus registers of the module from the controller console using the utility modbus-utils-rpc or modbus_client.
Without a Wiren Board controller, use the Wiren Board device web configurator or other software; see Using Wiren Board Modbus devices without a controller. You will need a computer with an interface converter: USB-RS485.

Our devices are continually improved. If settings described in this manual are missing, update the device firmware and controller software.

Current transformer configuration

WB-MAP3E CT and phase-mapping settings in the controller web interface

If meter configuration was ordered with the meter and CTs, CT parameters are already stored and each CT is labelled with its channel number. Connect each to that channel; otherwise readings will be incorrect.

If configuration was not ordered, enter the CT parameters into meter memory before use; otherwise readings will be incorrect.

Actual CT parameters vary between units. Wiren Board-supplied CTs are bench-calibrated and their parameters are printed on the CT label.

Each CT has two required configuration parameters:

Turns Lx — transformation ratio,
Phi Lx — phase correction.

Write both parameters for every CT to meter memory before operation.

Configuration Current Transformer Reverse x — inverts CT polarity.

If these settings are missing from the web interface, the controller software is older. Alternatively configure the CTs from the console.

Phase mapping configuration

Use phase mapping carefully: assigning a CT to the wrong voltage phase produces incorrect readings that may still look plausible. Each WB-MAP3E current channel can be associated with any voltage phase connected to the meter.

Phase mapping changes the factory CT-to-voltage assignment. For example, the L1 current input can measure a conductor carrying phase L2. This can correct wiring assignment errors in software. Mapping only selects which phase voltage the meter uses for calculations; it does not change the wiring or power connections.

If a voltage phase has no CT assigned to it, the parameters Urms and Upeak cannot be measured and appear in red in the web interface. Measuring VoltageAngle requires the CTs to be assigned to different phases.

Set phase mapping with Actual Phase Lx — the actual phase assigned to current transformer Lx.

If these parameters are absent, the controller software is older. See alternative configuration methods under Configuration methods.

Indicators

The meter has two front-panel LEDs:

S (green) — Modbus communication status: lights up when low-voltage power is applied and flashes during polling over RS-485. On devices with events enabled in Fast Modbus ⚡ the indicator flashes more frequently than during sequential polling because events are polled faster. In bootloader mode it flashes once per second; during firmware upload it flashes rapidly.
CF — flashes with energy consumption: 1000 pulses correspond to 1 kWh of total three-phase active energy.

Wiren Board controller web interface

Selecting a template

To display the device on the Devices tab of the Wiren Board controller web interface, add it automatically by scanning for Wiren Board devices on RS-485 or manually by selecting the template WB-MAP3E fw2.

For devices manufactured before autumn 2019 with firmware earlier than 2.1, use the template without fw2. The firmware version is printed on the enclosure label in the field FW.

Viewing readings

The controller web interface displays meter readings. Change the displayed channels in the device settings on the template selection page.

For all web-interface parameter names, see WB-MAP measured parameters, errors and web-interface names

Modbus operation

Wiren Board devices use Modbus RTU. The physical connection uses the RS-485.

interface. All main commands for reading and writing one or multiple registers are supported. See the list in the Modbus protocol description.

The module can be configured:

in the Wiren Board controller web interface;
using the Wiren Board device web configurator;
using third-party software.

Default port settings

Value default	Parameter name in the web interface	Parameter
9600	Baud rate	Baud rate, bit/s
8	Data bits	Number of data bits
None	Parity	Parity
2	Stop bits	Number of stop bits

In current firmware, setting Stop bits is optional: the device also operates correctly when its number of stop bits differs from the Modbus master setting.

For a faster response, we recommend increasing the baud rate to 115200 bit/s; see Communication parameter settings

Modbus address

Each device on the bus must have a unique address from 1 to 247. The factory-assigned address is printed on labels on the enclosure (top cover, side or underside). Devices in a production batch are assigned different addresses, so devices in one order will usually have different addresses.

For instructions on finding, changing or resetting the address, see Wiren Board device Modbus address.

Fast Modbus extension

Fast Modbus extends standard Modbus with rapid discovery of Wiren Board devices on RS-485 and event polling.

These features are enabled by a special command from the master, so Wiren Board devices remain compatible with third-party equipment.

Not every register supports event generation. Check the register map: event-capable registers are marked with ⚡. See Fast Modbus.

Register map

The meter provides numerous Modbus registers for measured and calculated quantities and for device control.

Modbus registers for measured and calculated quantities.

WB-MAP3E control register table.

Firmware updates and resetting settings

Wiren Board devices support firmware updates over Modbus. This allows bugs to be fixed at the installation site and, where technically possible, new features to be added. Settings stored in the device are retained during a firmware update.

Instructions:

New firmware releases are listed in the firmware changelog.

Factory calibration and CT parameters are stored separately and are not erased by firmware updates.