Reliable DC Current Measurement and Monitoring with Chen Yang Hall Current Sensor CYHCT-L21K
1. Introduction – Why Current Sensor Matters
In modern power electronics and industrial systems, accurate current measurement has become a basic design requirement. It underpins energy management and efficiency analysis, supports Industry 4.0 concepts such as precise monitoring and predictive maintenance, and is essential for safety functions like overload detection and short-circuit protection. In EV charging, battery storage, and renewable energy converters, current feedback is also the key input for control algorithms, efficiency optimization, and long-term performance tracking. For many designers, a split-core Hall effect current sensor provides a practical way to obtain this feedback without cutting cables or interrupting the system.
As a result, as these applications move to higher power levels, higher voltages, and longer service lifetimes, the demand for precise, reliable, and long-term stable current transducers continues to grow. Figure 1 summarizes the role of current measurement in three core aspects. Therefore, CYHCT-L21K was developed for exactly this environment: a compact through-hole (open-loop) Hall-effect current sensor that provides galvanically isolated DC current measurement while keeping a small footprint and flexible system integration.
To support system designers, this article will walk through how CYHCT-L21K works in real applications and what you should look at when selecting a current transducer. You can jump directly to the following sections:
2. Product Overview – Meet CYHCT-L21K
CYHCT-L21K is a split-core, open-loop Hall-effect DC current transducer designed for galvanically isolated measurement of DC and DC pulse currents in the 25–500 A range (depending on the selected model variant). It converts the primary current into a standard voltage or current output (0–5 V, 0–10 V, 0–20 mA, or 4–20 mA), making it easy to interface with PLCs, data loggers, and control electronics. For readers who would like to understand the sensing principle in more depth, we have a dedicated background article: Hall-Effect Current Sensors: An Introduction.
Structurally, CYHCT-L21K uses a through-window split-core design: the primary conductor simply passes through the opening, and the sensor can be clipped around existing cables without disconnecting them. The compact, panel-mount housing is suitable for dense control cabinets, and optional connectors (Molex or Phoenix, depending on the part number) simplify wiring in standardized industrial environments. Figure 3 shows a typical installation with the sensor clipped around an existing cable.
Typical users of CYHCT-L21K include industrial control equipment manufacturers, energy and power-electronics designers, power supply and inverter OEMs, and system integrators who need a ready-to-use, isolated DC current sensing module rather than a discrete, component-level solution.
Key product highlights (USPs)
- DC and pulsed current measurement – designed for DC currents and DC pulse/PWM waveforms in the 25–500 A range (model dependent).
- High galvanic isolation – open-loop Hall-effect design with reinforced insulation between primary and secondary circuits, suitable for high-voltage DC buses.
- Low power consumption – typical supply current ≤ 25 mA (plus output current for current-output versions), ideal for continuous monitoring.
- High reliability and long service life – industrial-grade construction with IP20 housing, overload capability, and MTBF ≥ 100,000 hours.
- Wide operating temperature range – specified from −40 °C to +85 °C, allowing use in demanding indoor and outdoor applications.
3. Technical Specifications
CYHCT-L21K is specified as a split-core, open-loop DC current transducer with a wide choice of current ranges and output types. The table below summarizes the most relevant parameters from the official datasheet in a compact form.
Parameter |
Value / Options |
Notes |
Measurement Range |
25 A – 500 A DC
(model-dependent) |
--- |
Accuracy |
Voltage output:
±1.0% for 25A–49A, ±0.5% for 50A–500A 4–20 mA output: ±1.0% for 25A–49A, ±0.5% for 50A–500A 0–20 mA output: ±1.0% for 25A–500A |
Suitable for precise monitoring and protection tasks where percentage-level accuracy is required.
|
Supply Voltage |
+12 V, +15 V, or +24 V DC
(model-dependent) |
Selected via the “n” code in the part number. |
Output Signals |
0–5 VDC, 0–10 VDC,
0–20 mA DC, 4–20 mA DC |
Depending on the “x” code in the part number. |
Operating Temperature |
−40 °C ~ +85 °C
Storage: −55 °C ~ +100 °C |
--- |
Mounting |
Panel Screw Mounting |
--- |
Case Style / Window Size |
L21K with aperture Ø21 mm |
--- |
Current Consumption |
≤25 mA for voltage output,
25 mA + output current for current output |
--- |
Response Time |
< 1 ms (DC output) |
--- |
The figure below shows the mechanical dimensions, window openings, and pin assignments of the CYHCT-L21K, which helps users properly allocate PCB and panel space.
For practical use, several parameters are particularly noteworthy:
- The wide current range (25–500 A) and 5× overload capability make the sensor flexible for different busbar and cable sizes.
- The combination of up to ±0.5% full-scale accuracy, good linearity, and DC–20 kHz bandwidth is well suited for both static DC measurements and dynamic DC pulse/PWM signals.
- 3 kV galvanic isolation and a –40…+85 °C operating range ensure that the sensor can be used safely in high-voltage, high-temperature industrial and renewable-energy environments with long expected lifetime.
For a full overview of all electrical and mechanical ratings, please refer to the official datasheet. If you are unsure which current range or output type best fits your system, our technical team will be happy to help – simply send us a message via our contact form.
4. Key Benefits & Unique Features
As one of our development engineers summarizes:
“CYHCT-L21K offers a rare combination of compact size, electrical isolation, and stable analog performance—ideal for system designs where space and reliability matter.”
From a customer’s point of view, CYHCT-L21K is not “just another Hall sensor,” but a practical building block that makes current measurement safer, easier and more predictable in real systems.
4.1 Which pain points does it solve?
🙋♂️ “I need to measure high DC current without putting my PLC at risk.”
- In many systems, the DC bus runs at high voltage and high current; directly inserting a shunt into that path exposes low-voltage electronics to dangerous potentials.
- CYHCT-L21K uses a Hall-effect, open-loop principle with galvanic isolation between primary conductor and secondary circuit, so the control side only ever sees a safe, isolated signal.
🙋♀️ “I don’t want to cut existing cables or shut down production just to add a sensor.”
- Retrofitting current measurement often means cutting thick cables or busbars, re-terminating lugs, and scheduling downtime.
- With CYHCT-L21K’s split-core, window structure, you simply open the housing, clip it around the existing conductor, and close it again – no cutting, no re-crimping, and minimal interruption to the system.
🙋 “My system has both steady DC and fast pulses – the sensor must see both.”
- PV inverters, battery chargers and DC drives rarely produce ‘perfect’ DC; there are ripple, pulses, or fast load changes.
- CYHCT-L21K is specified for DC and DC-pulse currents, with enough bandwidth to follow rapid changes, so the output reflects the real current waveform instead of a heavily averaged value.
🙋♂️ “There is hardly any free space left in my cabinet.”
- In compact combiner boxes or control cabinets, adding anything new is a struggle.
- CYHCT-L21K has a slim, panel-mount housing with a 21 mm window and can be combined with the CY-DRA88 DIN-rail adapter, so it fits neatly alongside breakers and terminals without demanding a lot of extra space.
🙋♀️ “I need accurate measurement, but closed-loop transducers are overkill for my budget.”
- High-end closed-loop or fluxgate sensors offer very high accuracy but are often too expensive for every feeder or string.
- CYHCT-L21K targets the “sweet spot”: good accuracy and linearity in the typical 25–500 A range, with a simple open-loop architecture that keeps cost and complexity reasonable.
4.2 Practical benefits for users and system integrators
For end users / operators
- Safer measurement path – Galvanic isolation keeps the PLC / monitoring device away from high bus voltages.
- Clear visibility of loading – Continuous current feedback helps spot overloads, imbalance or abnormal consumption early.
- Easy retrofits – Split-core design lets you add measurement without cutting cables or stopping the system for long.
- No extra power loss – The main conductor only passes through the window, so there is virtually no additional I²R loss.
- Reliable under real-world conditions – Designed for outdoor / industrial temperature ranges, so readings remain usable over time.
For system integrators, panel builders and OEMs
- One mechanical platform, many variants – Same housing and window size across multiple current ranges and output types.
- PLC-ready signals – Standard analog outputs (voltage or current, depending on version) connect directly to common I/O cards.
- Fast installation and replacement – Split core plus plug-in connector and optional DIN-rail adapter speed up panel wiring and service.
- Simple scaling and commissioning – Nearly linear transfer function makes scaling in PLC / microcontroller code straightforward.
- Balanced performance vs. cost – Open-loop architecture offers “good enough” accuracy for most DC feeders without closed-loop pricing.
5. Typical Applications
CYHCT-L21K is designed for the types of DC current paths engineers deal with every day. Whether it’s a PV string, a motor drive, or a battery module, the sensor fits naturally into many real-world systems.
1. Industrial Automation & Robotics
For example, in modern factories, every motor, actuator and robot arm depends on stable DC power. Engineers use current feedback to detect overloads, protect drives, and optimize energy usage.
- DC-bus monitoring in servo drives and variable-speed motors
- Overload / stall detection in robotic actuators
- Power tracking in compact motion-control modules
2. Solar Energy & Energy Storage Systems (ESS)
In practice, PV strings and battery packs need continuous current feedback to ensure safe operation, detect mismatch, and maintain system efficiency—especially as modules age.
- PV string current measurement for mismatch or shading diagnosis
- Charge/discharge monitoring in battery packs and small ESS
- DC-bus feedback in inverter and power conversion stages
3. EV Charging & Low-Power Mobility Systems
In real-world systems, many low to mid-power EV chargers (10–30 A class) require isolated DC measurement for load control, safety interlocks, and internal protection.
- Current sensing in wallbox chargers and onboard DC/DC modules
- Load monitoring for small EV chargers and mobility power blocks
- Protection feedback in auxiliary converters
4. Power Supplies & UPS Systems
Telecom power units, SMPS modules and UPS systems use DC current monitoring to control output stability and protect backup circuits.
- Output current sensing in SMPS / telecom power shelves
- Backup current feedback in UPS rectifiers
- Protection triggers for DC rails and distribution feeders
5. Building Automation & HVAC
Modern HVAC and building systems increasingly use efficient DC motors and actuators; current feedback helps keep them running smoothly and safely.
- Monitoring DC fans, blowers and pump actuators
- Detecting abnormal load in HVAC compressors
- Integration into building management systems (BMS)
6. Home Appliances & Consumer Devices
Inverter-based appliances rely on BLDC/FOC motors, where DC current gives a direct indication of motor load, health and efficiency.
- Current sensing in inverter AC units, washing machines, refrigerators
- Motor blockage / overload detection
- Feedback for energy-optimized appliance controllers
Conclusion
In summary, CYHCT-L21K brings together the qualities that engineers and users look for in a modern DC current sensor:
- Compact form factor that fits easily into crowded cabinets
- Accurate, repeatable measurement across its rated range
- Galvanic isolation for safe integration with PLCs and control electronics
- DC and DC-pulse capability for real-world power systems
- Stable, easy-to-integrate analog output, compatible with common industrial I/O
Whether you are working on PV strings, battery packs, UPS systems or low-power EV chargers, CYHCT-L21K provides a practical, reliable way to add isolated current feedback without redesigning your system.
If you would like to explore more details, you can access:
- Datasheet: Hall Effect DC Current Sensor CYHCT-L21K
- Product page: CHENYANG Aufklappbarer Hall-Effekt DC Stromsensor CYHCT-L21K
- Technical support: info@chenyang-gmbh.com
If you need different current ranges or expert advice on choosing the right model, simply contact us — we’re happy to support you.