Pepperl+Fuchs CJ1 Series Proximity Sensors

Technical Dossier

Product Details And Specifications

Pepperl+Fuchs CJ1 Series: Comprehensive Module Range and Technical Overview

The Pepperl+Fuchs CJ1 series represents a standardized family of capacitive proximity sensors engineered for continuous-duty deployment in heavy industrial environments. These sensors are installed across global process industries including petrochemical refineries, chemical processing plants, nuclear facility auxiliary systems, pulp and paper mills, and food-grade production lines. The CJ1 series is characterized by its cylindrical M12 housing, flush and non-flush mounting variants, and compatibility with both NPN and PNP switching outputs — making it one of the most widely specified capacitive sensor families in distributed control system (DCS) and PLC-based field instrumentation architectures.

The series operates on the principle of capacitive field disturbance detection, enabling reliable sensing of non-metallic targets including liquids, granulates, powders, and glass — a capability that distinguishes it from inductive sensor families. Its robust IP67/IP68 ingress protection rating and wide operating temperature range make it suitable for outdoor installations and wash-down environments.

The Evolution of CJ1 Architecture

The CJ1 series was introduced by Pepperl+Fuchs as part of its standardized cylindrical sensor platform, sharing the M12 form factor with the inductive NBB and NJ families to allow interchangeable mounting hardware across sensor types. Early CJ1 variants featured fixed sensitivity and analog-compatible discrete outputs. Subsequent generations introduced adjustable sensitivity via external potentiometer, enabling field calibration without sensor replacement — a critical feature for bulk material level detection applications where target dielectric constants vary by batch.

The transition from 2-wire DC to 3-wire DC configurations (NPN/PNP selectable) addressed compatibility requirements across Siemens S7, Allen-Bradley ControlLogix, and Yokogawa CENTUM DCS input card specifications. Later variants incorporated IO-Link communication capability, enabling parameterization, diagnostics, and process value transmission over a single standard cable — aligning the CJ1 platform with Industry 4.0 field device integration standards.

As of 2024, the CJ1 series is in a mature lifecycle phase. Pepperl+Fuchs continues to supply standard variants, while select non-flush long-range models have transitioned to recommended successor types within the CJ series. Operators maintaining legacy installations should prioritize spare parts inventory to avoid unplanned downtime during extended maintenance cycles.

CJ1 Full Catalog & Functionalities (SKU List)

The following SKUs represent verified, commonly stocked models within the Pepperl+Fuchs CJ1 capacitive proximity sensor series. Models are classified by output type, mounting style, and sensing range.

Capacitive Sensors – Non-Flush, NPN Output

• CJ1-12GK-N: M12 non-flush capacitive sensor, 4 mm range, NPN NO, 10–30 VDC, IP67
• CJ1-12GK-N-Y187: M12 non-flush, NPN NO, 4 mm, extended cable variant, IP67
• CJ1-12GK-N2: M12 non-flush, NPN NC output, 4 mm sensing range, 10–30 VDC
• CJ1-18GK-N: M18 non-flush capacitive sensor, 8 mm range, NPN NO, 10–30 VDC, IP67
• CJ1-18GK-N2: M18 non-flush, NPN NC, 8 mm sensing range, 10–30 VDC
• CJ1-30GK-N: M30 non-flush capacitive sensor, 15 mm range, NPN NO, 10–30 VDC, IP67
• CJ1-30GK-N2: M30 non-flush, NPN NC, 15 mm sensing range, 10–30 VDC

Capacitive Sensors – Non-Flush, PNP Output

• CJ1-12GK-P: M12 non-flush capacitive sensor, 4 mm range, PNP NO, 10–30 VDC, IP67
• CJ1-12GK-P2: M12 non-flush, PNP NC output, 4 mm sensing range, 10–30 VDC
• CJ1-18GK-P: M18 non-flush capacitive sensor, 8 mm range, PNP NO, 10–30 VDC, IP67
• CJ1-18GK-P2: M18 non-flush, PNP NC, 8 mm sensing range, 10–30 VDC
• CJ1-30GK-P: M30 non-flush capacitive sensor, 15 mm range, PNP NO, 10–30 VDC, IP67
• CJ1-30GK-P2: M30 non-flush, PNP NC, 15 mm sensing range, 10–30 VDC

Capacitive Sensors – Flush Mount Variants

• CJ1-12GK-N-Y1: M12 flush-mount capacitive sensor, 2 mm range, NPN NO, 10–30 VDC, IP67
• CJ1-18GK-N-Y1: M18 flush-mount capacitive sensor, 5 mm range, NPN NO, 10–30 VDC, IP67
• CJ1-30GK-N-Y1: M30 flush-mount capacitive sensor, 10 mm range, NPN NO, 10–30 VDC, IP67

Sourcing Hard-to-Find & Obsolete CJ1 Parts

DriveKNMS maintains a dedicated inventory program for Pepperl+Fuchs CJ1 series sensors, including models that have been discontinued or transitioned to limited-availability status. For process plants operating on 10–25 year maintenance cycles, the ability to source exact-match replacement sensors — without re-engineering mounting brackets, cable assemblies, or DCS input card configurations — is operationally critical.

Our sourcing network covers new-old-stock (NOS) units, factory-refurbished sensors with full functional verification, and cross-referenced equivalent models where direct replacements are unavailable. All sourced units are matched against original Pepperl+Fuchs part numbers and datasheet specifications before dispatch. Customers requiring batch quantities for planned shutdowns or turnaround maintenance events are accommodated with priority lead times.

Quality Control for the CJ1 Range

Each CJ1 series sensor processed through DriveKNMS undergoes a structured functional verification protocol prior to shipment. Testing procedures are adapted to the specific output configuration and sensing range of each model:

• Supply voltage sweep test across the rated 10–30 VDC operating range to verify stable switching behavior at voltage extremes
• Sensing range verification using calibrated dielectric target (water-equivalent permittivity) at rated distance and 80% of rated distance
• Output state verification for both NO and NC configurations under load
• Leakage current measurement on NPN open-collector outputs to confirm compatibility with low-threshold DCS input cards
• Cable and connector integrity check: continuity, insulation resistance, and M12 connector seating torque
• IP67 seal inspection: housing thread condition, O-ring presence, and potting integrity at cable entry

Sensors that fail any parameter are quarantined and not returned to available inventory. Test records are retained per unit for traceability.