In environmental protection projects (sewage, waste gas, solid waste, photovoltaic energy storage grid connection, etc.), reliably transmitting current signals from equipment such as fans, pumps, dosing, heating, and oxidation to PLC/SCADA systems is the first step to ensuring energy conservation , stability, safety , and operational maintenance .

The HEYI Electric KCT-L series is designed for this purpose : open-type, Hall effect principle, DC 4–20 mA, single-shuttle current measurement, capable of measuring AC/DC/pulse currents, and providing sufficient isolation to minimize downtime for retrofits.

What is a KCT-L DC 4-20mA current transmitter

HEYI’s open-type (detachable) open-loop Hall effect current sensor:

The primary and secondary sides are fully electrically isolated, providing high safety and easy wiring . Test data indicates an insulation withstand voltage of 5 kV/1 minute (50 Hz).

The signal terminal is an industrial-friendly DC 4–20 mA with a zero point of 4 ± 0.1 mA. It outputs linearly with AC/DC/pulse current and can be adapted to the analog input of any PLC/host computer.

The power supply is optional , 12V or 24V , which is fully compatible with common distribution boxes and grounding boxes at environmental protection sites .

Model and range:

KCT-16L/24L/36L three opening sizes, with a variety of ranges from 50 A to 600 A to choose from, covering fan pump rooms to small and medium-sized busbars.

HEYI products have excellent indicators :

high precision/good linearity, low temperature drift, fast response, strong anti-interference, and strong overload capacity – these are hard indicators for complex working conditions (such as inverter PWM and strong electromagnetic interference).

Supports customization (OEM):

Different rated input/output specifications can be made. This is very critical for power project construction .

In terms of environmental protection, what are some typical application scenarios

(1) Sewage treatment plant: blower/lift pump/return pump

Use current to observe the load: pipe blockage, impeller scaling, aeration head loss, the current will “speak first”; connect the DC 4-20 mA to the PLC for interlocking/early warning.

Not afraid of variable frequency: The Hall solution can also measure non-sinusoidal waves and pulse currents output by VFDs, enabling earlier diagnosis.

(2) Waste gas treatment: RTO/activated carbon/scrubber fan

“Unstable air volume” = Look at the current curve: if the filter element is clogged or the valve position is abnormal, the current will slowly increase; use the current trend to trigger “check first, then shut down” to reduce emergency response.

Strong interference field: The split design of KCT-L 4-20mA current transmitter gives it excellent isolation + anti-interference properties , the signal will hardly be affected , and there is no need to add isolators everywhere.

(3) Desulfurization, denitrification and dust removal: applications of circulating pumps, induced draft fans, ash hopper equipment, etc.

Energy efficiency closed loop: Map current to load factor and formulate energy-saving strategies for DCS/SCADA;

Excellent environmental adaptability : HEYI KCT-L 4-20mA current transmitter covers an operating temperature range of -40 to +85°C and can also be used in outdoor cabinets.

(4) Ozone/UV/heating system

Checking health: When the power supply or module degrades, the current will first deviate;

Fast response to leakage : millisecond- level response allows for efficient fault removal.

(5) New energy grid connection and park-side energy management

Photovoltaic/DC bus: The KCT-L 4-20mA current transmitter is directly targeted at “PV new energy” and “grid monitoring”, and is DC/AC/pulse compatible, making it perfectly suitable for branch monitoring and bus protection .

How to connect the KCT-L 4-20mA current transmitter at the construction site 

Threading: Only thread one conductor to be measured (phase line/busbar), and do not thread the round-trip lines of the same circuit together, otherwise the magnetic flux will cancel out and no reading can be made.

Power supply: connect to +12/24V and GND;

Signal: Iout (4–20mA) enters the PLC/acquisition module analog input, and the common terminal is connected to GND.

Note : Wrong wiring may damage the sensor. Please check the terminal definition again before connection (common markings: 1:+24V, 2:GND, 3:Iout, 4:GND).

Pay attention to these 5 points in product appearance

Customization of different products

Opening size: 16L/24L/36L. Select according to the cable/busbar. It is best if it can pass through without being loose.

Range: 1.2–2.0 times the typical operating current of the device (to provide margin without sacrificing resolution).

Output/power supply:

Default is 4–20mA, 12/24 V. If the system requires 0–5 V/0–10 V or a special connector, OEM customization is the most worry-free.

Environment and interference:

The product’s built-in isolation/anti-interference features can cover most VFD sites; keep as much distance as possible from high-power contactors and magnetic components.

Dynamic requirements:

For transient/pulse working conditions, take advantage of its fast response and stop relying on “after-the-fact alarms”.

How to make OEM customization requirements more efficient?

Let’s make the “three-piece set” clear at once:1

Primary side: cable/busbar size, typical/peak current, AC or DC/pulse;
(2) Secondary side:

signal standard (4–20mA or voltage/switch), connector type, cable length;
(3) Installation:

opening/guide rail/clamp, installation space restrictions, whether logo/inkjet printing is required.

The KCT-L 4-20mA current transmitter natively supports “customization of different rated inputs and outputs”, with low processing and communication costs and fast delivery.

Visible value after launch

Energy efficiency:

Use current × voltage × power factor to estimate power/power consumption, forming a “kWh per cubic meter of air volume/per ton of water” graph, and energy savings are visible to the naked eye.

Reliability:

“Current alarm first” before the rotating equipment fails, providing early warning to avoid sudden shutdown events .

Compliance and traceability:

All DC 4–20mA standard signals can be recorded in the SCADA historical database, and annual inspections and third-party assessments can be verified with data.

Easy maintenance and operation :

open structure, less downtime for maintenance or adding or modifying points, which is very critical to the KPI of environmental protection projects.

Summarize

The KCT-L current transmitter is a lightweight solution for converting current into useful data in environmental protection scenarios:

quick installation, smooth connection, accurate measurement, and interference resistance.

It offers direct standard 4–20mA operation and customizable OEM options, enabling simultaneous monitoring of equipment status, improved energy efficiency, and safety .

Compay：HEYI Electrical Co., Ltd.

Brand: HEYI/ASCT

Contact: Bethy

E-mail: heyi@heyiele.com             

Tel: 86-13968747975

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