Honeywell CSNS Series Current Sensors – CSNS300M-500

Technical Dossier

Product Details And Specifications

Honeywell CSNS Series Technical Notes

The Honeywell CSNS (Current Sensor) series represents a standardized family of closed-loop Hall-effect current transducers engineered for continuous-duty measurement in high-reliability industrial environments. These devices are deployed across chemical processing plants, petroleum refineries, nuclear power auxiliary systems, offshore platforms, and heavy manufacturing facilities where accurate, galvanically isolated current measurement is a non-negotiable operational requirement. The CSNS series occupies a well-established position in the global industrial instrumentation market, with installed bases spanning legacy DCS architectures (Honeywell TDC 3000, Experion PKS) and third-party PLC/SCADA systems requiring standardized analog feedback signals. Their compact form factor, wide measurement range, and 5 VDC supply compatibility make them a preferred transducer for motor drive feedback loops, power distribution monitoring, and UPS current monitoring in mission-critical facilities.

The Evolution of CSNS Architecture

The CSNS series was developed as Honeywell's response to the industrial market's demand for a compact, PCB-mountable current transducer with a standardized output interface. Early-generation Hall-effect sensors in industrial applications required bulky toroidal cores and external signal conditioning circuits. The CSNS architecture internalized the compensation winding, the Hall element, and the signal conditioning amplifier into a single molded package, reducing installation footprint and eliminating external calibration requirements.

The series uses a closed-loop (compensated) Hall-effect topology. In this architecture, the magnetic flux generated by the primary current is continuously nulled by a compensation current driven through a secondary winding. The output is a proportional current (or voltage, depending on the variant) that mirrors the primary current with high linearity and low temperature drift. This design provides galvanic isolation between the primary conductor and the measurement circuit, a mandatory requirement in high-voltage industrial environments.

Across its production lifecycle, the CSNS series has maintained backward-compatible pinouts and supply voltage requirements (typically ±15 VDC or +5 VDC depending on sub-family), allowing direct replacement of earlier units without PCB redesign. As the series has matured, Honeywell has introduced variants with extended measurement ranges (up to 500A nominal) and enhanced EMC shielding for use in variable-frequency drive (VFD) enclosures where high-frequency switching noise is prevalent. The series is now in a mature/sustained phase; while active production continues for core SKUs, several low-volume variants have transitioned to last-time-buy or obsolete status, making aftermarket sourcing a critical consideration for maintenance teams.

CSNS Full Catalog & Functionalities (SKU List)

The following SKUs represent the verified CSNS series product range. Units are classified by measurement range and output type. All models use closed-loop Hall-effect topology with galvanic isolation.

CSNS300M-500: 300A nominal, ±500A peak, current output, PCB mount, ±15 VDC supply.
CSNS100M-500: 100A nominal, ±500A peak range, current output, PCB mount, ±15 VDC supply.
CSNS150M-500: 150A nominal, closed-loop Hall-effect, current output, ±15 VDC supply.
CSNS200M-500: 200A nominal, closed-loop, current output, PCB mount, ±15 VDC supply.
CSNS250M-500: 250A nominal, closed-loop Hall-effect, current output, ±15 VDC supply.
CSNS400M-500: 400A nominal, closed-loop, current output, PCB mount, ±15 VDC supply.
CSNS500M-500: 500A nominal, maximum range variant, current output, ±15 VDC supply.
CSNS50M-500: 50A nominal, compact closed-loop, current output, PCB mount, ±15 VDC supply.
CSNS75M-500: 75A nominal, closed-loop Hall-effect, current output, ±15 VDC supply.
CSNS300M-033: 300A nominal, 3.3 VDC single-supply variant, voltage output, PCB mount.
CSNS100M-033: 100A nominal, 3.3 VDC single-supply, voltage output, low-power applications.
CSNS200M-033: 200A nominal, 3.3 VDC single-supply, voltage output, PCB mount.
CSNS150M-033: 150A nominal, 3.3 VDC single-supply, voltage output, PCB mount.
CSNS50M-033: 50A nominal, 3.3 VDC single-supply, voltage output, compact PCB mount.
CSNS75M-033: 75A nominal, 3.3 VDC single-supply, voltage output, PCB mount.
CSNS400M-033: 400A nominal, 3.3 VDC single-supply, voltage output, high-current PCB mount.
CSNS500M-033: 500A nominal, 3.3 VDC single-supply, voltage output, maximum range variant.

Sourcing Hard-to-Find & Obsolete CSNS Parts

For obsolete or low-volume CSNS variants, DriveKNMS provides: RFQ-reviewed sourcing status availability checks within 24 hours; cross-reference analysis to identify functional equivalents within the CSNS family or from compatible third-party transducer manufacturers; and long-term supply agreements for facilities requiring guaranteed access to specific SKUs over multi-year maintenance cycles. All units are stored in ESD-safe, climate-controlled warehousing to preserve sensor calibration integrity.

Quality Control for the CSNS Range

Each CSNS unit processed by DriveKNMS undergoes a structured verification protocol prior to dispatch. The closed-loop Hall-effect architecture requires functional testing under load conditions to confirm compensation circuit integrity; bench-level visual inspection alone is insufficient for this sensor family.