Purchase now: Wago 750-439 NAMUR Input Module
Purchase now: Atlantech Drives provides you the Wago 750-439, a specialized **2-Channel Digital Input Module** designed for **NAMUR sensors** in hazardous environments. This module is typically classified as **Intrinsically Safe (Ex i)**, meaning it includes integrated safety barriers (isolators) that limit the energy delivered to the sensor, preventing sparks that could ignite explosive atmospheres (Zone 0/1). It reads the status of proximity sensors, level switches, or mechanical contacts located in the hazardous area.
Technical Specifications and Diagnostics
The 750-439 supplies a defined voltage (approx. 8.2V) to the NAMUR sensor. It detects not only the «On/Off» state but also **Wire Break** and **Short Circuit** conditions. If the current drops near zero (wire cut) or spikes (short), the module sends a diagnostic error to the PLC and lights up a Red LED. This eliminates the need for external Zener barriers in the control cabinet, saving massive amounts of space and wiring time.
- Part Number: 750-439 (Ref NAMUR Series).
- Channels: 2 Digital Inputs.
- Sensor Type: NAMUR (DIN EN 60947-5-6).
- Protection Type: Ex i (Intrinsically Safe).
- Diagnostics: Short Circuit / Wire Break.
- Signal Current: On < 1.2 mA / Off > 2.1 mA.
- Installation: Zone 2 (Module) -> Zone 0/1 (Sensor).
- Bit Width: 2 bits data + 2 bits diag.
Expert Installation Advice: Blue Housings
Ex i modules are special. Expert Tip: Wago Ex i modules usually have a **blue housing** or a blue flag to distinguish them. You must install them in a dedicated block, powered by an Ex i Supply Module (like 750-625) which separates the «safe» 24V bus from the «intrinsically safe» power. Never place a standard white/grey module in the middle of the blue Ex i block, as it violates the safety clearance distances (creepage and clearance).
Frequently Asked Questions (FAQs)
Q: Can I connect a standard mechanical switch?
A: Yes, but to use the wire break supervision, you must install a specific resistor network (1kΩ / 10kΩ) at the switch contacts so the module sees the correct NAMUR current levels.
Q: Is this compatible with all couplers?
A: Yes, it works with standard PROFINET, Ethernet, or Modbus couplers, provided the power supply segment is configured correctly for Ex i.
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