Definition
Metering refers to the ability of IoT devices to measure, record, and report physical quantities such as electricity, flow, and usage. Metering is a core function of charging stations, smart meters, and energy equipment. It collects metering values such as electricity (kWh), power (kW), current, and voltage through metering modules, and reports them to charging platforms and energy monitoring platforms, supporting billing, settlement, remote meter reading, and load analysis. Combined with MeterValues, metering data is transmitted in a standardized way via protocols such as OCPP and OCPI. In cross-border scenarios, metering data needs to support multi-country settlement, multiple currencies, and multiple time zones, and terminals need to support one card for multiple countries to ensure data return for cross-border charging scenarios.
Technical Features and Architecture
The metering technology architecture includes: Metering Module — hardware such as electricity meters, current transformers, and voltage sampling, supporting accuracy levels (e.g., 0.5 class, 1 class); Data Acquisition — real-time collection of electricity, power, metering values , supporting event-triggered reporting and periodic reporting; Protocol Integration — OCPP MeterValues, OCPI CDR, DLMS/COSEM (smart meters), MDB (EV charging station payment metering), etc.; Settlement and Billing — integrating metering data with charging platforms and charging operation platforms , supporting cross-border settlement. Combined with remote meter reading , it enables remote consumption data collection; combined with energy monitoring , it supports load analysis and energy efficiency management.
Application in IoT and cross-border scenarios
Metering is widely applied in: Charging Billing — EV charging stations and charging stations power metering and billing, metering values are reported to charging operation platforms via OCPP; Smart Meters — remote meter reading and consumption analysis for water meters, gas meters, and electricity meters ; Energy Monitoring — energy monitoring and microgrids power and electricity metering; Cross-border Charging — the metering data of overseas EV charging stations is transmitted back to domestic platforms via IoT SIM cards, supporting OCPI cross-border settlement. Cross-border charging networks and global energy management rely on metering for accurate billing and data interoperability.
SimtoLink provides connectivity for metering devices covering over 200 countries, facilitating data reporting for cross-border charging, remote meter reading, and other scenarios.
Units, precision, and accumulation rules come before the report
Metering is the process by which a measuring device samples, accumulates, and presents a reading of energy, power, flow, or elapsed time. An instantaneous value says how fast things are at this moment. A cumulative value says how much there has been since a register baseline. The two cannot stand in for each other: power can swing widely while energy still grows steadily. An accuracy class states the allowed error range. It does not mean the reading will always equal the true physical quantity. A report in international IoT only sends a reading that has already been formed. Cellular success does not improve meter accuracy, and an outage should not make the total inside the meter run backward.
Before a metering result is used for settlement, state the unit, the decimal places, when the register resets, and how clock error is handled. If one side of a cross-border site splits energy by a local tariff period, the period boundary must come from the agreed time zone, not from wherever the platform server sits. Periodic reports suit reconciliation. Event reports suit a limit crossing. Reconciliation must be able to obtain the starting and ending register readings. Average power alone is not enough. After a current transformer or a pulse constant is replaced, the old total and the new total are kept as separate segments, or a change of ratio is seen as a jump in consumption. The interval stored in the meter should be longer than the time a cross-border retry may take.
Treating the last heartbeat as the energy used for settlement
The last power value the platform received is often multiplied by the offline duration to estimate energy. If the device stopped or changed load while it was offline, that product has no metering meaning. The right step is to wait until the meter recovers and read the difference between the register before and after. Another error is to add the same register reading each time a retry delivers it, so the bill doubles after roaming recovers. A cumulative message needs a meter sequence number or a monotonic register reading. The platform overwrites by reading, rather than adding by message count.
Converting units once in each of several systems also produces a stable factor error, while the interface still returns success. Convert only once at the boundary, and keep the original reading. When time synchronization fails, time-of-use energy falls into the wrong period. That is a time problem, not sensor drift. A measurement reported with IEC 61850 and a pulse total inside a charger are two sources. They should not be merged into one register just because the numbers are close. A management platform may trigger a meter read, but it should not hand-edit a register baseline in the file to "line up" a bill.
Reconciliation takes the register readings of the same meter at two instants. The difference is the energy for that interval. Missing heartbeats in between do not affect that method, provided the register did not reset and the ratio was not changed. If a reset is found, calculate in segments and keep the last reading from before the reset.