DocumentationWB-MAP3E known issues
ERRMODBUS001: Device replies to address 0xFD
Affected devices
WB-MAP* devices with firmware earlier than 2.10.0.
Description
Fast Modbus devices can interfere with third-party devices on the same bus if those devices use special commands beginning with 0xFD.
Cause and details
Fast Modbus reserves 0xFD for special broadcast commands. If a third-party request starts with 0xFD but uses a command outside Fast Modbus, affected Wiren Board devices reply with MODBUS_ERR_ILLEGAL_FUNCTION, disrupting the other exchange. The bus driver incorrectly treats the packet as ordinary Modbus traffic.
Workaround
Avoid sharing a bus between affected Wiren Board and third-party devices.
Resolution
Fixed in firmware 2.10.0.
ERRMODBUS002: Incorrect response to discovery command 0x46
Affected devices
WB-MAP* devices with firmware earlier than 2.8.0.
Description
Fast Modbus originally used function 0x60, later changed to 0x46 because 0x60 was in a reserved range. Backward compatibility retained both request codes, but the device always replied with 0x60. The fix replies with the same function used in the request: 0x46 or 0x60.
Remedy
Update firmware to 2.8.0.
Resolution
Fixed in firmware 2.8.0.
ERRMODBUS003: Unexpected behaviour when invalid values are written to some registers
Affected devices
WB-MAP* devices with firmware earlier than 2.10.4.
Description
When values in the range [256 ... 65535] are written to some registers, the upper 8 bits are discarded and the firmware receives the value modulo 256. For example, writing 257 has the same effect as writing 1.
The device address register (128) is one affected register.
All registers work as expected within their documented ranges. The issue occurs when invalid values above 255 are written.
Remedy
Update firmware to 2.10.4.
Resolution
Fixed in firmware 2.10.4.
ERRMODBUS004: Incorrect bit-field replies
Affected devices
WB-MAP* devices with firmware earlier than 2.8.0.
Description
Replies containing bit fields, including coil/discrete reads and event management, could contain incorrect high bits.
Remedy
Update firmware to 2.8.0.
Resolution
Fixed in firmware 2.8.0.
ERRMODBUS006: Responses to requests with incorrect parity
Affected devices
WB-MAP* devices with firmware earlier than 2.10.1.
Description
The device replied to requests with incorrect parity instead of ignoring them.
Remedy
Update firmware to 2.10.1.
Resolution
Fixed in firmware 2.10.1.
ERRMODBUS007: Lost events when two devices transmit simultaneously on one bus
Affected devices
WB-MAP* devices with firmware earlier than 2.13.0.
Description
When two devices on one bus have pending events simultaneously, one may transmit an incomplete event packet.
Cause and details
In Fast Modbus, the master requests events. All devices with pending events arbitrate; the winner replies, while the others wait for the next request.
A generated event waits for transmission. After the device places its frame on the bus, the event is marked sent. The master's next acknowledgement for that device removes the sent events from its queue. This is the normal acknowledgement mechanism.
The defect marked events as sent too early, on receipt of the event request, before arbitration finished. If the device won arbitration, operation was normal. If it lost, no packet was transmitted, but its events were already marked sent. A subsequent acknowledgement for that device also acknowledged these unsent events, removing them from the queue before they ever reached the master.
The web-interface value does not update and no MQTT message is published, although the device registers remain correct. The change notification is lost.
For example, if inputs on two relay modules on the same bus close simultaneously, one module may update correctly in the web interface while the other loses some events and still appears in its previous state despite physically switching.
Workaround
Temporarily disable event-based operation for affected registers by setting sporadic to false in the device template. The registers will then be polled at the configured interval.
Resolution
Fixed in firmware 2.13.0.
ERRMODBUS008: Unexpected behaviour with long request frames
Affected devices
WB-MAP* devices with firmware earlier than 2.14.0.
Description
Receiving a frame longer than 265 bytes, the maximum Fast Modbus frame length, can freeze and reboot the device; settings may also be lost in some cases.
Cause and details
The receive algorithm did not handle oversized invalid requests, causing a buffer overflow and corruption of adjacent memory. The device freezes and the watchdog restarts it. Very large frames, above approximately 500 bytes, can also corrupt settings, causing a restart with default communication parameters: 9600 8N2, address 1.
Workaround
- Do not send requests exceeding the limits of Modbus RTU or Fast Modbus (265 bytes for Fast Modbus).
- Do not connect the device to a bus carrying non-Modbus traffic or messages longer than 265 bytes.
Resolution
Fixed in firmware 2.14.0.
ERRMODBUS009: Unexpected behaviour when reading near address 0xFFFF in continuous-reading mode
Affected devices
WB-MAP* devices with firmware earlier than 2.14.0.
Description
With continuous-reading mode enabled, a read range reaching or crossing address 0xFFFF can freeze and reboot the device.
Cause and details
The continuous-reading algorithm did not handle overflow of the 16-bit register-address counter. Reading 0xFFFF wrapped the counter and caused an infinite loop, followed by a watchdog reset.
Workaround
With continuous-reading mode enabled, do not read a range including 0xFFFF. Wiren Board devices have no implemented register at that address.
Resolution
Fixed in firmware 2.14.0.
ERRMODBUS010: Incorrect request validation and handling of invalid requests
Affected devices
WB-MAP* devices with firmware earlier than 2.14.0.
Description
The device may accept or mishandle syntactically invalid requests, return an incorrect exception code, or impose an incorrect register-count limit.
Cause and details
The validation algorithm mishandles these cases:
1) Requests to read zero registers succeed with an empty-data reply containing only a header and CRC. Modbus requires exception 0x03 (ILLEGAL_DATA_VALUE).
2) A single limit of 125 registers is applied to all read/write functions; exceeding it returns 0x02 (ILLEGAL_DATA_ADDRESS). Modbus instead specifies limits of 2000 bits for bit reads, 125 registers for input/holding reads, 1968 coils for multiple-coil writes, and 123 holding registers for multiple-register writes. Exceeding the applicable limit should return 0x03 (ILLEGAL_DATA_VALUE).
3) Byte Count is not validated for multiple writes (0x0F and 0x10). A mismatch between Byte Count and register count should return 0x03 (ILLEGAL_DATA_VALUE).
4) Single-coil writes do not validate the value and use the most significant bit of the request value. Modbus permits only 0x0000 and 0xFF00; all other values should return 0x03 (ILLEGAL_DATA_VALUE).
5) Structurally invalid requests with a valid CRC, such as overlong requests, are processed normally. Such malformed requests should instead be ignored.
6) Structurally valid but oversized frames of 257–265 bytes are processed. Standard Modbus frames longer than 256 bytes are invalid and should be ignored.
Workaround
Send only structurally correct requests compliant with the Modbus specification.
Resolution
Fixed in firmware 2.14.0.
ERRMODBUS011: Incorrect handling of invalid Fast Modbus event-configuration requests
Affected devices
WB-MAP* devices with firmware earlier than 2.14.0.
Description
An event-configuration command (EVENT_CTRL, cmd=0x46, sub_cmd=0x18) with invalid length fields can configure event notifications incorrectly and produce a reply of unpredictable length.
Cause and details
The Fast Modbus event-configuration handler did not validate the size and internal data-block length fields. Invalid lengths can cause it to process data beyond the received frame, resulting in:
1) Incorrect event notification settings, including spontaneous changes to event priorities or masks.
2) An event-configuration reply of unpredictable length.
Workaround
Send only valid Fast Modbus commands compliant with its specification.
Resolution
Fixed in firmware 2.14.0.
ERRMAP0001: Loss of configuration and calibration data
Affected devices
WB-MAP12H, WB-MAP3H, WB-MAP3E and WB-MAP6S with firmware 2.2.0 through 2.2.4 inclusive
Description
The device shows incorrect voltages and zero values for all powers. Current readings (Irms) are present but may be incorrect. Modbus registers 0x1490–0x1495 contain zeros.
The problem occurs after some time in service. Its triggering conditions are not fully understood, but low ambient temperature and interference from nearby motors and contactors may contribute.
Cause and details
Low temperature and interference can occasionally trigger an emergency microcontroller reset. This is usually invisible to the user, but in very rare cases the reset can corrupt the meter nonvolatile memory holding calibration constants, transformer settings and accumulated energy. Corrupted memory resets to its uncalibrated factory state.
All WB-MAP devices with firmware 2.2.0–2.2.4 inclusive are potentially affected, but the problem is extremely rare. Its probability increases with operating time.
Resolution
Fixed in firmware 2.2.5 dated 10 March 2020.
Recommendations
Users of WB-MAP devices with firmware 2.2.0–2.2.4 inclusive are advised to update to the latest firmware. Quick-update commands for the Wiren Board controller:
dpkg -s wb-mcu-fw-updater || (apt update && apt install wb-mcu-fw-updater) wb-mcu-fw-updater update-all
Files for users without Wiren Board controllers are available here.
If affected, contact sales directly for warranty replacement, or technical support for remote reflashing and calibration-table restoration.
ERRMAP0002: Configuration and calibration data loss during firmware updates
Affected devices
All WB-MAP* devices
Description
In some cases, a WB-MAP device may show zero readings after a firmware update. Reflashing again does not resolve the problem.
Cause and details
If the device is not in its bootloader during flashing, part of the firmware may overwrite configuration and calibration data, causing incorrect readings.
Resolution
Fixed in firmware 2.5.2 dated 8 June 2023. Updating also restores operation of devices affected by this problem.
ERRMAP0003: Nonzero voltage readings with incorrect meter wiring
Affected devices
All three-phase WB-MAP meters with firmware up to and including 2.6.0.
WB-MAP3EV is unaffected because it uses different circuitry.
Description
Due to the circuit design, applying voltage to one phase without protective earth connected to PE can produce nonzero readings on disconnected phases. This does not occur in installations following the installation instructions and the electrical installation rules that require grounding instrument-transformer secondary windings.
All three conditions must occur simultaneously:
- The meter PE terminal is not connected in the panel.
- One or two phases are lost, rather than all three.
- There are no other loads on those phases. The meter must be the only load on its cable; any other connected equipment would pull the phase to zero through its load.
For example, someone connects the meter on a workbench for testing without connecting PE to protective earth.
Cause and details
For safety, WB-MAP meters use a neutral attenuation network: the measurement circuitry is isolated from both phase voltages and neutral. The ADC ground potential is connected to PE but not to neutral.
With PE disconnected, its potential depends on the vector sum of connected phases and the divider ratios in the isolation networks. For example, with 230 V on one phase, the others may reach approximately 230 V * 0.3/1.3 = 53 V.
Resolution
Fixed in firmware 2.6.1 dated 7 July 2023.
Added logic that clears voltage readings and related power readings when a phase voltage is below 30% of the highest of the three phase voltages.
Starting with version 2.6.3 this logic can be disabled using Detect phase outages in the template, or by writing 0 to register 102.
ERRMAP0004: Calculation error at small RMS current and voltage values
Affected devices
All WB-MAP devices, including WB-MAP3EV.
Description
At low currents and voltages, calculation error affects the least significant digits.
For example, at zero or near-zero current or voltage, the device returns 0.029 A or 0.018 V.
This does not affect device accuracy or accumulated energy values.
Cause and details
The metering chip measures instantaneous current and voltage, calculates power and energy, then derives the other parameters from them.
At small currents and voltages, calculation error affects the least significant digits, but does not accumulate into calculation results and does not depend on calibration coefficients.
Accuracy is unaffected because this error remains below the specified instrument accuracy at any current or voltage. Power and energy have no such error; there is no no-load energy accumulation.
Resolution
Fixed in firmware 2.6.1 dated 7 July 2023. Voltage or current readings and related powers are now set to zero below 0.02 V or 0.03 A respectively (0x0001 E000 in hexadecimal).
ERRMAP0005: Class X2 capacitors on the PE line
Affected devices
MAP3E v1.6A, v1.6B, v1.6C and MAP3ET with the same revisions
Description
The power-supply input circuits use class X2, 310 VAC capacitors between PE and L/N for interference suppression. This is a class Y connection and requires the corresponding capacitor class.
Cause and details
The MAP3E power supply was redesigned to meet CE conducted-emissions requirements, but the selected capacitors did not fully match the operating conditions. This increases the risk of high voltage at PE. With standard 230/400 VAC mains and reliable PE grounding, this alone does not cause an operating problem. Nevertheless, although the capacitors withstand at least 1300 V, the manufacturer considers their selection incorrect and has taken corrective action.
Workaround
– Continue operation after confirming that input phase RMS voltage does not exceed 310 VAC (approximately 530 VAC line-to-line) and PE is reliably grounded. – Alternatively, request warranty replacement from technical support, citing this erratum.
Resolution
Starting with revision 1.6C/1.
ERRMAP0006: Incorrect error code when reading voltage from an unconfigured phase
Affected devices
All three-phase WB-MAP meters with firmware up to and including 2.5.2.
Description
32-bit voltage registers return 0xFFFF, the 16-bit error code, instead of the correct 32-bit error code 0xFFFF FFFF.
Cause and details
Three-phase WB-MAP versions allow reassignment of phases to channels. This supports three separate loads on a single-phase supply or corrects phase assignments when transformers were installed on the wrong phases.
If no channel uses a phase, reading its voltage register should return the 32-bit error code 0xFFFF FFFF and show a red voltage reading in the template. Instead, the 16-bit error code 0xFFFF is returned and the template shows 0.01 V.
Resolution
Fixed in firmware 2.6.0 dated 6 June 2023.
ERRMAP0008: Incorrect total power calculation
Affected devices
All three-phase WB-MAP meters of hardware revisions v1.2F or v1.2K, and all WB-MAP3H/WB-MAP12H models with firmware 2.6.1–2.7.3 inclusive.
Description
The sum of individual phase powers and the reported total power differ by several times.
Cause and details
WB-MAP meters use ATM90* chips to measure and calculate electrical parameters and consumption for each phase separately. Firmware additionally calculates total power across phases; the error affects this calculation.
WB-MAP revisions v1.2F and v1.2K use ATM90E36A instead of ATM90E32AS. These chips store power in different register formats, so firmware converts readings for ATM90E32AS compatibility.
WB-MAP3H and WB-MAP12H also use ATM90E36A.
Firmware 2.6.1 introduced fixes for ERRMAP0003 and ERRMAP0004, disrupting the conversion sequence and producing incorrect total power. WB-MAP3H and WB-MAP12H do not convert readings to ATM90E32AS format, but ATM90E36A total-power storage causes the same problem.
Individual phase power accuracy is unaffected. Updating the firmware restores correct total power.
Resolution
Fixed in firmware 2.7.4 dated 20 October 2023. Update the device firmware following the instructions.
ERRMAP0009: Incorrect units for the peak reset period
Affected devices
All WB-MAP meters with peak measurement and firmware up to and including 2.7.4
Description
The peak reset subsystem interpreted the register value as milliseconds instead of seconds.
Resolution
Fixed in firmware 2.7.5 dated 8 November 2023. Update the device firmware following the instructions.
ERRMAP0010: Incorrect line-to-line voltage calculation
Affected devices
All three-phase WB-MAP meters with firmware up to and including 2.7.5.
Cause and details
Line-to-line voltages are calculated from phase voltages and phase angles.
A firmware bug caused two problems:
- Register overflow at near-zero phase angles. For example, connecting one phase to several WB-MAP inputs could produce line-voltage register readings of 650 V.
- The calculation used the angle between the wrong pair of phases. For example, calculating L1–L2 voltage used the L2–L3 angle.
Resolution
Fixed in firmware 2.8.0; update the device firmware.
ERRMAP0011: Possible phase-angle measurement error as capacitors age
Affected devices
All WB-MAP devices except WB-MAP3EV, batches MAP3E v1.2C–V1.6G, MAP12E v1.7J–V1.10C and MAP6S v1.2–v1.5C
Cause and details
The current-channel antialiasing filters used ceramic capacitors with excessive capacitance. Aging may cause a noticeable phase-angle error and, in some cases, a small active power/energy error.
In the worst assumed case, a current-channel capacitor loses 20% of its capacitance over the service life while other capacitors remain unchanged. The estimated phase-angle error would be −0.36 degrees (leading).
The effect on active power/energy depends on the load. For a nearly resistive load, the error is negligible; at larger voltage-to-current phase angles it may become noticeable. At 45 degrees (cos(phi)=0.7), it may reach 0.63%.
These are worst-case estimates; the actual effect is expected to be several times smaller.
Remedies
This is a hardware issue that requires component replacement to eliminate. Affected devices can be recalibrated on the manufacturer's test bench.
Ceramic capacitor aging slows logarithmically and is fastest in the first hours, days and months after soldering. Older devices should therefore exhibit little further drift after recalibration.
Resolution
Fixed starting with batches:
- MAP3E — v1.6H,
- MAP12E — v1.11,
- MAP6S — v1.5D
ERRMAP0012: Phase-delay calibration error
Affected devices
All WB-MAP devices except WB-MAP3EV, batches:
- WB-MAP3E: v1.2L/4-v1.6F/2
- WB-MAP12E: v1.7O/2-v1.10B/2
- WB-MAP6S: v1.2C–v1.5C
- WB-MAP3ET: v1.2C-v1.4A
Cause and details
A production calibration error causes a phase-angle measurement error of approximately 0.25 degrees (lagging). This remains within the declared 0.5S accuracy class (more about accuracy classes here)
The active power/energy error depends on the load. For a nearly resistive load it is negligible; at larger phase angles it becomes noticeable. At 45 degrees (cos(phi)=0.7), it reaches 0.31%.
Workaround
Affected devices can be recalibrated on the manufacturer's test bench.
Alternatively, add a 0.25-degree correction to the current transformer phase delay:
- In the Wiren Board controller web interface, add 250 to the WB-MAP settings Phi Lx (transformer phase shifts)
- Using Modbus registers, add 250 to the values in registers 0xX460, 0xX461 and 0xX462, where X is the channel number. Using Wiren Board Modbus devices without a controller.
Resolution
Fixed since January 2024, starting with batches:
- WB-MAP3E: v1.6F/3
- WB-MAP12E: v1.10B/3
- WB-MAP6S: v1.5C/1
- WB-MAP3ET: v1.4A/1
ERRMAP0014: Device freezes with no indication
Description
Strong electromagnetic interference, for example from a contactor, may cause the device to freeze and its indicators to go out. Power cycling restores operation.
Affected devices
WB-MAP devices from batches:
- WB-MAP3E: v1.6F - v1.8A
- WB-MAP6S: v1.5C - v1.8A
- WB-MAP3ET: v1.4A - v1.4E
Cause and details
EEPROM latch-up causes the microcontroller supply voltage to drop. Power cycling the board clears the problem. Its probability is extremely low and depends on many factors.
Workaround
- Affected devices are replaced under warranty.
Resolution
- WB-MAP3E: fixed in v1.8B
- WB-MAP6S: fixed in v1.8B
- WB-MAP3ET: fixed in v1.4F
ERRMAP0016: Excessive initial active and reactive energy values on new devices
Affected devices
- WB-MAP3E: v1.7A, v1.8A, v1.8B;
- WB-MAP12E: v1.13A, v1.13A/1, v1.13A/2;
- WB-MAP3ET: v1.4E, v1.4E/1;
Cause and details
During production, the device is flashed and then calibrated. A firmware bug accumulated active and reactive energy before calibration. All new measurements after calibration are correct. The previous incorrect values, hundreds of kWh/kvarh, remain in memory but do not affect current measurements.
Resolution
Fixed since April 2025, starting with batches:
- WB-MAP3E: v1.8A/1, v1.8B/1;
- WB-MAP12E: v1.13A/3;
- WB-MAP3ET: v1.4E/2;
Workaround
No user action is required; the devices measure correctly.
ERRMAP0018: Rectifier diode failure in the phase-voltage power supply
Affected devices
All WB-MAP3E devices earlier than v1.11 and WB-MAP12E earlier than v1.14.
Cause and details
Isolated rectifier diode failures occurred when meters were installed near inductive loads such as pumps and motors. S1M rectifiers are used in pairs, each rated at 1 kV, tolerating approximately 1.6 kV negative-polarity surges: 2 kV minus the downstream filter capacitor voltage. This is occasionally insufficient.
Resolution
Replaced the diodes with higher-voltage EMA520 (2 kV) devices starting with WB-MAP3E v1.11 and WB-MAP12E v1.14.
Workaround
Warranty replacement in case of failure.
ERRMAP0019: Incorrect line-to-line voltages when phase angles are unavailable
Affected devices
All three-phase WB-MAP meters with firmware earlier than 2.12.4.
Cause and details
Line voltages are calculated from phase voltages and interphase angles. When angle reading or calculation failed, for example with a disconnected phase, the code continued calculating and returned incorrect values instead of an error indication highlighted red in the interface.
Resolution
Fixed in firmware 2.12.4: line-to-line voltages return an error indication when no valid interphase angle is available.
ERRMAP0021: Conflicting storage of disconnected-phase detection and current-transformer inversion settings
Affected devices
All WB-MAP meters except WB-MAP3EV with firmware 2.10.0–2.12.3.
Cause and details
Disconnected-phase detection and L2 current-transformer inversion may take incorrect values. For six-channel meters, this means channel 2 of six single-phase channels; for twelve-channel meters, L2 of the first three-phase channel. A firmware bug stored these independent settings in overlapping nonvolatile memory. Actual settings may differ from requested settings, and changing one may unexpectedly change the other.
Resolution
The source states that a future firmware update will fix this. After updating to a corrected version, disconnected-phase detection will be enabled; change it again if required.
Workaround
Use only the combinations that the device handles correctly:
– Disconnected-phase detection enabled, L2 current-transformer inversion disabled; or – Disconnected-phase detection disabled, L2 current-transformer inversion enabled.
If neither combination is suitable, physically reverse the L2 current transformer by turning it around or swapping its leads.
ERRMAP0022: Incorrect voltage-to-current phase angles when voltage is absent
Affected devices
All WB-MAP meters with firmware earlier than 2.12.4.
Cause and details
Voltage-to-current phase angles require valid current and voltage measurements. When voltage measurement failed, the device continued returning incorrect phase angles.
Resolution
Fixed in firmware 2.12.4: voltage-to-current phase angles return 0 when the corresponding voltage measurement is unavailable.