Topworx TXP-M21GNPM4A1 Explosion-Proof Valve Position Transmitter Limit Switch
The Topworx TXP-M21GNPM4A1 Valve Position Transmitter is a heavy-duty, explosion-proof discrete valve monitor manufactured by Emerson under the Topworx TXP series product line.
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- Fast dispatchAustralia & worldwide
- Technical supportTalk to an engineer
- 1 YearWarranty
Product Overview
The Topworx TXP-M21GNPM4A1 Valve Position Transmitter is a heavy-duty, explosion-proof discrete valve monitor manufactured by Emerson under the Topworx TXP series product line. Engineered specifically for quarter-turn rotary pneumatic actuators and industrial valves, this compact switch box delivers reliable electrical position feedback and local visual indication directly to plant operators and distributed control systems. It is constructed to operate reliably in harsh, hazardous plant environments subject to explosive gases, combustible dusts, and severe weather exposure.
Built with an ultra-compact, epoxy-coated aluminium housing, the TXP-M21GNPM4A1 incorporates two SPDT mechanical microswitches with fine-resolution visual position indication. Its internal mechanical design features cam-operated switch triggers that allow rapid, precise field calibration without the need for specialized tools. Standardized with a NAMUR VDI/VDE 3845 drive shaft and mounting pattern, the unit integrates smoothly onto automated ball valves, butterfly valves, and plug valves across offshore platforms, chemical processing plants, oil refineries, and industrial flow systems.
Technical Specifications
| Specification | Value |
| Product Name | Discrete Valve Position Monitor / Limit Switch Box |
| Manufacturer / Brand | Topworx / Emerson |
| Model Number | TXP-M21GNPM4A1 |
| Product Series | Topworx TXP Series |
| Housing Enclosure Material | Cast Aluminium with Industrial Epoxy Coating |
| Switch Configuration | 2 × SPDT Mechanical Microswitches |
| Electrical Contact Rating | 15A at 125/250 VAC, 0.5A at 125 VDC |
| Visual Indicator | High-Visibility Red / Green Rotary Beacon Indicator |
| Shaft / Drive Standard | NAMUR VDI/VDE 3845 (Direct Drive) |
| Drive Shaft Material | Stainless Steel |
| Conduit / Cable Entries | 2 × 1/2 Inch NPT Conduit Entries |
| Ingress Protection Rating | IP66 / IP67 / NEMA 4, 4X |
| Hazardous Location Approvals | ATEX / IECEx / UL / CSA (Flameproof / Explosion-Proof) |
| Operating Temperature Range | -40°C to +80°C (-40°F to +176°F) |
| Mounting Bracket Type | Standard NAMUR Mounting Pattern Compatibility |
| Target Valve Type | Quarter-Turn Rotary Valves and Actuators |
| Operating Medium Compatibility | Outdoor, Marine, Corrosive Industrial Atmospheres |
| Condition | New |
| Warranty | 1 Year |
Key Features
Explosion-proof and flameproof aluminium enclosure rated for hazardous industrial locations
Dual SPDT mechanical microswitches providing independent open and close electrical signals
High-visibility continuous red and green indicator beacon for rapid visual status verification
Quick-set color-coded cams allowing fast, accurate field position calibration
Robust epoxy-coated cast aluminium body delivering high resistance to marine corrosion
Double conduit entries providing convenient wiring access and clean terminal routing
Stainless steel drive shaft built to standard NAMUR dimensions for direct actuator coupling
Weatherproof IP66 and IP67 ingress protection safeguarding internal components from moisture
Proven mechanical durability ensuring long cycle life under severe vibration and temperature cycling
Typical Applications
Quarter-turn automated ball, butterfly, and plug valve position monitoring
Pneumatic rotary actuator position feedback in distributed control systems (DCS)
Oil and gas upstream offshore platforms, FPSO vessels, and refinery manifolds
Chemical and petrochemical processing line automated safety loops
Power generation steam distribution, gas turbine lines, and boiler feed valves
Water and wastewater treatment automated flow regulation skids
Industrial process automation and emergency shutdown (ESD) valve assemblies
Shipping & Support
Fast dispatch: Australia & Worldwide Shipping
Technical assistance available
1-year warranty
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