Two-wire current transmitter: Integrated vs. Split type

—In-depth analysis current transmitter of Korean IoT energy monitoring and smart power distribution market

In Korea’s industrial and building energy management systems, current monitoring devices are rapidly upgrading from traditional meters to real-time data nodes that can be connected to IoT gateways.

Especially in BEMS, FEMS, smart factories, and photovoltaic systems, two-wire 4-20mA current transmitter have become the most stable, standard, and PLC/gateway compatible sensing layer devices.

There are two main ways that technology is being used right now.

Integrated current transmitter (Integral / Solid-core transmitter)

Split-core/Dismountable transmitter

The two exhibit significantly different application ecosystems in Korean market.

1.Characteristics current transmitter of Market Demand in Korea (Key to Product Selection)

South Korea isn’t just a place where things are cheap, it’s a market that has really high standards and a huge need for change, plus a lot of people are using the internet to connect all sorts of devices.

Typical characteristics:

(1) The renovation of existing structures far exceeds the construction of new ones.

Many industrial buildings in Korea were constructed between 1990 and 2010.

Therefore, prolonged power outages are not permitted, busbar removal is not allowed, and production disruptions are not permitted.

This directly led to:

In some parts of the world, people really like split-type products, way more than in Europe or the US.

(2) Gateway access commonly uses analog signals.

In Korea, the usual setup for smart power monitoring is like this:

Sensor → 4-20mA → PLC / DAQ → RS485 → IoT Gateway → Cloud EMS

reason:

EMC stable

Long-distance anti-interference

Easy to pass KC certification

Compatible with older systems

Therefore, two-wire transmitters are more readily adopted than RS485 sensors.

(3) Energy policies drive high-density monitoring points

Korea’s K-RE100 energy standard and energy-efficient building regulations require:

Sub-circuit metering

Equipment-level energy consumption

Real-time monitoring

This means:

There may be 20 to 80 current measuring points in the same distribution cabinet.

Therefore, installation cost becomes a key decision-making factor.

1.Integrated True RMS Current Transducer (Solid-core)

Working structure

The wire must pass through a closed iron

At its core, this means a really stable setup and the best possible magnetic connection.

Advantage

（1） Highest accuracy and stability

Magnetic circuit closed → Minimal leakage flux,

lowest temperature

drift, and small long-term drift

Suitable:

• Precision Measurement
• Power quality analysis
• Billing-level system

（2）Strong resistance to electromagnetic interference

Korean-made inverters feature high density and integration, resulting in greater stability against high-frequency harmonics.

（3） Lowest long-term maintenance cost

The structure is robust

and unaffected by vibration.

shortcoming

（1）Power must be disconnected before installation.

In Korea, it’s common for factories to say no when it comes to taking out stitches.

This is the biggest business obstacle.

（2）High installation labor costs

Wages in Korea are a lot higher compared to many countries in Southeast Asia.

installation time > equipment costs.

Typical applications in South Korea

Scene Reasons for adoption

New semiconductor factory Precision priority

Electricity company metering Extremely high stability requirements

UPS / Data Center Backbone Long-term reliability

III. Split-core ammeter

(Open-end Hall effect sensor/open-end CT + two-wire transmitter module)

Working structure

The iron core can be opened to clamp the cable

without disconnecting the power.

Advantage

That’s a huge advantage, especially in a country like Korea where having uninterrupted power supply is crucial. Not having to shut off the power to install it is a major benefit, making the whole process much more convenient and efficient.

In Korea, it’s seen as really important, something they can’t do without.

Downtime costs >> Sensor costs

especially:

• Commercial buildings
• Hospital
• subway
• semiconductor production line

Two, the installation process is really quick, it’s more than ten times faster than what you’d normally expect.

Installation completed in 1 minute,

suitable for batch renovation projects

（3）More suitable for IoT gateway deployment

Korean energy monitoring systems are often retrofitted.

Project features:

• Install dozens to hundreds of measuring points at a time
• Short construction period
• Nighttime construction

Split-type designs have almost become the default solution.

It can work with loads that use direct current, or ones that need a device to change the frequency, like those that have sensors called Hall effect sensors.

High proportion of new energy sources (photovoltaics, energy storage, EV charging)

make it impossible for traditional CT scanners to measure DC current.

shortcoming

The accuracy is slightly lower compared to the closed-type.

Air gaps cause incomplete magnetic circuit closure, making

temperature drift more sensitive.

（2） Installation Dependency Operation Guidelines

• Loose fit → Increased error
• Typical applications in South Korea
• Scene reason
• Commercial building EMS renovation Uninterrupted power supply construction
• Photovoltaic and Energy Storage Monitoring Measurable DC
• Factory equipment-level energy consumption Multiple measurement points
• Batch deployment of IoT gateways Quick installation
• EV charging station High frequency and DC hybrid

5.Comparison of IoT Gateway Access Perspectives

project Integrated split type

Retrofit Modification ❌Difficulty ✅Best

Large-scale measurement points ❌High cost ✅Ideal

Accuracy billing ✅Best ⚠Medium

New energy DC ❌Regular CT scans are not sufficient. ✅ Hall effect support

Installation time slow Extremely fast

Korean market acceptance middle Very high

6.Market Conclusion (Korea)

In Korea:

New projects tend to be integrated, while renovation projects almost always opt for modular designs.

South Korea’s core growth in energy digitalization comes from:

energy-saving retrofitting of old buildings + IoT EMS deployment.

Therefore, the market structure is:

Split type ≈ Mainstream

integrated type ≈ Special scenarios

Compay：HEYI Electrical Co., Ltd.

Brand: HEYI/ASCT

Contact: Bethy

E-mail: heyi@heyiele.com             

Tel: 86-13968747975

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