Iskra WM3M4 (MID EV meter)

Status: Vendor Confirmed · Register points: 73 · Transports: Modbus RTU

A curated ModDef profile for the Iskra WM3M4 (MID EV meter). Import it as iskra.wm3m4 or load the .moddef.yaml directly.

Connect to one over Web Serial and watch its values live in the device dashboard.

Usage

Load the profile, bind a transport, and read a point by name. The runtime applies the offset, scaling, byte order, and sentinels from the definition.

Go

doc, _ := moddef.Load("iskra-wm3m4.moddef.yaml")
dev, _ := client.New(doc, "iskra-wm3m4", transport) // your modbus.Transport
v, _ := dev.ReadPoint(ctx, "frequency")
fmt.Println(v)

TypeScript

import {Device} from '@moddef/core';
import {loadDocument} from '@moddef/core/node';

const doc = await loadDocument('iskra-wm3m4.moddef.yaml');
const dev = Device.create(doc, 'iskra-wm3m4', transport);
console.log(await dev.readPoint('frequency'));

Rust

let doc = moddef_core::load("iskra-wm3m4.moddef.yaml")?;
let mut dev = Device::new(&doc, Some("iskra-wm3m4"), transport)?;
let v = dev.read_point("frequency").await?;

Python

from moddef import Device, load
from moddef.pymodbus import Options, PymodbusTransport

doc = load("iskra-wm3m4.moddef.yaml")
transport = await PymodbusTransport.tcp("192.168.1.50", options=Options())
dev = Device.create(doc, "iskra-wm3m4", transport)
print(await dev.read_point("frequency"))

C

md_doc_t doc;
md_doc_init(&doc, flash_ptr, flash_len);        /* zero-copy view */

md_dev_t dev;
md_dev_init(&dev, &doc, MD_STR("iskra-wm3m4"), &transport);

md_value_t v;
md_dev_read(&dev, MD_STR("frequency"), &v);

C++

auto doc = moddef::Document::view(flash_bytes).value();   // zero-copy over flash
auto dev = moddef::Device::open(doc, "iskra-wm3m4", transport).value();

if (auto v = dev->read("frequency"); v)
    std::cout << v->to_string() << '\n';

Measurands

The 9 semantic quantities this device reports, each linked to the measurand catalog. Query a device by measurand instead of a raw point when you want portable code.

Base quantity	Name	Unit	Description
frequency	Frequency	Hz	Grid frequency
voltage	Voltage	V	RMS voltage; qualify with phase_ref (L1_N, L1_L2, ...)
current	Current	A	RMS current; qualify with phase_ref / direction
active_power	Active Power	W	Instantaneous real power
reactive_power	Reactive Power	var	Instantaneous reactive power
apparent_power	Apparent Power	VA	Instantaneous apparent power
power_factor	Power Factor	1 (ratio)	Ratio of real to apparent power (dimensionless)
energy_active	Active Energy	Wh	Cumulative active energy register
temperature	Temperature	degC	Temperature; qualify with location (INTERNAL, EXTERNAL, ...)

Source

• Profile: energy-meter/iskra-wm3m4/iskra-wm3m4.moddef.yaml
• Register map: vendor documentation