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S51-PA-5-A00-PK is an S51 Series M18 cylindrical photoelectric sensor manufactured by IDEC (formerly DATASENSOR). It adopts an axial retro-reflective design with PNP output, M12 4-pin connector, and a sensing distance of 4m, suitable for general industrial automation detection applications.
- Model Segment Definition (Precise Decoding)
| Segment | Code | Meaning |
| 1 | S51 | Product series code: S51 Series M18 cylindrical photoelectric sensor |
| 2 | PA | Optical type + mounting style: P=Plastic housing, A=Axial light emission (R=Radial) |
| 3 | 5 | Connection type: 5=M12 4-pin connector (2=2m fixed cable) |
| 4 | A00 | Function configuration: A=Standard retro-reflective (non-polarized), 00=Standard output setup (Light ON / Dark ON selectable) |
| 5 | PK | Output type + housing material: P=PNP output, K=Plastic housing (N=NPN, M=Metal) |
Full Model Definition:
S51 series plastic housing axial-emission retro-reflective photoelectric sensor, M12 connector, PNP output, standard functional configuration.
- Core Specification Parameters (Official Data)
| Parameter Category | Technical Specification | Remarks |
| General Information | ||
| Manufacturer | IDEC / DATASENSOR | Former DATASENSOR acquired by IDEC |
| Order No. | 952701261 | Official unique part code |
| Lifecycle Status | Obsolete | Marked on Mouser and other platforms |
| Housing Dimension | M18 cylindrical, plastic material | Flat design with 2 mounting holes for flexible installation |
| Electrical Parameters | ||
| Operating Voltage | 10…30VDC | Compliant with EN60947-5-2 |
| No-load Current | ≤35mA | Low power consumption design |
| Load Current | ≤100mA | PNP output driving capability |
| Output Voltage Drop | ≤2V @100mA | Low saturation voltage |
| Response Time | ≤1ms | High-speed detection |
| Switching Frequency | 1kHz | High-frequency switching performance |
| Optical Parameters | ||
| Detection Type | Retro-reflective (Non-polarized) | Standard type for conventional object detection |
| Sensing Distance | 4m | Used with standard reflector |
| Light Source | Visible red LED | Easy alignment and commissioning |
| Optical Axis Direction | Axial | Aligned with sensor central axis |
| Ambient Light Immunity | 10000lux (Daylight) | Strong anti-interference capability |
| Physical & Environmental | ||
| Protection Class | IP67 | Dustproof and waterproof, suitable for industrial environments |
| Operating Temperature | -25℃ ~ +55℃ | Wide temperature range |
| Storage Temperature | -40℃ ~ +70℃ | |
| Vibration / Shock Resistance | 10g / 50g | Excellent mechanical stress resistance |
| Connection Type | M12 4-pin connector | Pin assignment: 1=V+, 2=Output, 3=V-, 4=Test |
- Accessory List (Standard & Optional Parts)
| Accessory Name | Order No. | Description |
| Standard Accessories | ||
| Mounting Nut (Plastic) | G602000008 | 100 pcs per pack, for sensor fixation |
| Mounting Bracket | 95ACC5220 (JOINT-18) | Angle-adjustable mounting bracket |
| Reflector | 95ACC5… | Matches retro-reflective sensor, dedicated for 4m sensing distance |
| Optional Accessories | ||
| Protective Sleeve | G5000001 (MEK-PROOF) | Enhanced protection for harsh environments |
| M12 Connecting Cable | 95ACC… | Extension cables in multiple lengths available |
| Sensitivity Adjustment Tool | – | For models with adjustable sensitivity (e.g., suffix B01) |
- Alternative Brands & Cross Reference (Direct Replacement)
| Brand | Replacement Model | Key Matching Features | Difference Description |
| Omron | E3F3-R4B4 | M18, 4m retro-reflective, PNP, M12 | Faster response time 0.5ms, similar price |
| Siemens | 3RG6013-3AB00 | M18, 4m retro-reflective, PNP, M12 | IP67 rated, wider temperature range -25℃~+70℃ |
| Schneider | XUM2APCNL2 | M18, 4m retro-reflective, PNP, M12 | Built-in diagnostic LED, slightly higher price |
| Pepperl+Fuchs | RL31-8-H-4000-IR/47/105 | M18, 4m retro-reflective, PNP, M12 | Infrared light source, stronger ambient light resistance |
| IDEC Alternative | S51-PA-5-B01-PK | Upgraded same-series model | With sensitivity adjustment, 3.5m polarized type |
- Selection Guidelines & Alternative Solutions (Quick Reference)
Selection Rule
Three key factors for S51 selection: Optical type, Output type, Connection type
Optical Type: A=Axial retro-reflective, R=Radial retro-reflective, F=Through-beam, C=Diffuse reflective
Output Type: P=PNP, N=NPN
Connection Type: 5=M12 connector, 2=2m fixed cable
Quick Alternative Solutions
- Same Series Replacement: S51-PA-5-B01-PK (Polarized + sensitivity adjustment, ideal for reflective objects)
- Upgraded Replacement: S5N-PA Series (IO-Link support, intelligent diagnosis, longer sensing distance)
- Functional Replacement:
Through-beam application: S51-PA-5-F00-PK (20m sensing distance)
Diffuse reflective application: S51-PA-5-C01-PK (Fixed 10cm / Adjustable 1–40cm)
Application Scenarios
Packaging Production Line: Detect carton and film positioning; retro-reflective design resists dust interference
Conveyor System: Object presence detection; axial light emission suits side mounting on conveyors
Machine Tool Automation: Workpiece positioning detection; plastic housing anti-collision with IP67 protection
Logistics Sorting: Parcel dimension detection; 4m range covers most sorting line widths
- Air Freight Compliance & Certification
- Air Freight Compliance: No built-in lithium battery / supercapacitor, classified as general cargo for normal air shipment.
- Certifications:
CE: Compliant with EN60947-5-2
UL: Compliant with North American safety standards
RoHS: Eco-friendly materials complying with EU directives
- S51 Full Series Model List (Core Models)
| Model | Type | Sensing Distance | Output | Connection | Remarks |
| S51-PA-2-A00-PK | Axial Retro-reflective | 4m | PNP | 2m Cable | Basic version |
| S51-PA-5-A00-PK | Axial Retro-reflective | 4m | PNP | M12 | Current model |
| S51-PA-5-B01-PK | Axial Polarized Retro-reflective | 3.5m | PNP | M12 | With sensitivity adjustment |
| S51-PR-5-A00-PK | Radial Retro-reflective | 4m | PNP | M12 | Radial light emission |
| S51-PA-5-F00-PK | Through-beam Receiver | 20m | PNP | M12 | Matches separate emitter |
| S51-PA-5-C01-PK | Diffuse Reflective | 10cm / 1–40cm | PNP | M12 | Adjustable sensing range |
| S51-MA-5-A00-PK | Axial Retro-reflective | 4m | PNP | M12 | Metal housing |
The S51-PA-5-A00-PK is a cost-effective M18 retro-reflective photoelectric sensor. Featuring 4m sensing distance, PNP output, M12 connection and IP67 protection, it is a universal choice for industrial automation. Though obsolete, abundant same-series and cross-brand replacements are available. Model selection shall be precisely matched according to sensing distance, object property (reflective / non-reflective), installation space (axial / radial) and connection method.
