Top worx 81-20516-A4 - Explosion-Proof Position Sensing - Industrial ATEX

Product Specification

​1. Product Overview: Topworx 81-20516-A4 Valve Position Indicator

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The Topworx 81-20516-A4 is a rugged, high-performance valve position indicator designed for industrial automation applications requiring precise monitoring of valve status in harsh environments. Engineered with a durable stainless steel housing (IP66/IP67-rated), this device is built to withstand extreme conditions such as moisture, dust, vibration, and temperature fluctuations (-40°C to +85°C). It utilizes a non-contact magnetic sensing mechanism to detect valve position (open/closed) reliably, eliminating mechanical wear and ensuring long-term accuracy. The 81-20516-A4 is compatible with a wide range of valve types, including ball, butterfly, and gate valves, making it ideal for oil and gas, chemical processing, water treatment, and power generation industries.

​2. Key Technical Specifications​

• ​Output Signals: SPDT mechanical switch (5 A @ 250V AC) or proximity sensor (NPN/PNP).
• ​Supply Voltage: 24–240V AC/DC (universal input).
• ​Enclosure Rating: IP66/IP67, NEMA 4X.
• ​Housing Material: 316 stainless steel.
• ​Operating Temperature: -40°C to +85°C.
• ​Connection Type: 1/2" NPT conduit entry.
• ​Certifications: ATEX/IECEx (Zone 1/21), SIL 2/3 compliance.
• ​Mechanical Life: >1 million cycles.

​3. Industrial Applications and Use Cases

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The 81-20516-A4 is widely deployed in oil and gas pipelines to monitor valve positions in remote or hazardous locations. In chemical plants, it ensures safe operation by providing real-time feedback on corrosive fluid control valves. Water treatment facilities use it to track the status of large-diameter gate valves in pumping stations. The device also supports power generation systems, such as steam turbine bypass valves, where reliability under high-pressure conditions is critical. Its ATEX/IECEx certification makes it suitable for explosive atmospheres (Zone 1/21), including LNG terminals and fuel storage sites.

​4. Competitive Advantages and Unique Features​

• ​Non-Contact Sensing: Magnetic Hall Effect technology ensures zero mechanical wear and maintenance-free operation.
• ​Extreme Durability: 316 stainless steel construction resists corrosion, chemical exposure, and physical impacts.
• ​Universal Compatibility: Works with 24–240V AC/DC systems and integrates with PLCs, DCS, and SCADA platforms.
• ​Safety Compliance: ATEX/IECEx and SIL 2/3 certifications for hazardous area deployments.
• ​Easy Installation: Modular design allows field-adjustable cam settings and tool-free calibration.

​5. Functional Capabilities and Operational Benefits

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The 81-20516-A4 provides fail-safe valve status monitoring, triggering alarms or automated shutdowns during malfunctions. Its dual SPDT switch outputs enable redundant control loops for critical processes. The IP66/IP67 rating ensures uninterrupted performance in flooded or dusty environments, reducing downtime. By replacing mechanical limit switches, it lowers lifecycle costs and enhances system uptime. The device’s LED status indicator simplifies troubleshooting, while its universal voltage support streamlines integration into legacy or modern control systems. These features make it a cost-effective, future-proof solution for Industry 4.0-driven automation upgrades.

Packaging & Shipping

Company Information
Xiamen ZhiCheng Automation Technology Co., Ltdit is a leading global supplier of control system components. We specialize in control systems and drives.
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