DNS/VNS pressure and vacuum switches with stainless steel sensors (1.4571) are suitable for monitoring and controlling pressures in chemical plants, in process engineering and wherever the pressure of aggressive liquids and gases must be monitored.

All components of the sensor system are made of high-grade stainless steel (1.4571) and are welded using state-of-the-art processes without filler materials. The pressure sensor is seal-free and plasma-welded. It has a robust housing made of seawater-resistant die-cast aluminium GD Al Si 12.

The switching differential is not adjustable for DNS/VNS – 201 types. The switching differential is adjustable for DNS/VNS – 203 types. DNS/VNS – 351 types are chemical versions with a switch housing with chemical protection; the hysteresis is not adjustable for these types.

Features and benefits

• The DNS and VNS series are calibrated for falling pressure. This means that the adjustable switching pressure on the scale corresponds to the switching point at falling pressure. The reset point is higher by the amount of the switching differential.
• High-quality stainless steel components in the sensor system.

Certifications

• SIL2 according to IEC 61508-2.

Specifications

• Overall width: 112 mm
• Minimum operating ambient temperature: -25 °C
• Minimum media temperature: -25 °C
• Maximum operating ambient temperature: 70 °C
• Maximum media temperature: 70 °C
• Brand: FEMA | Honeywell
• Switch configuration: SPDT microswitch 250 V; capacity 5 A inductive, 8 A resistive
• Scale calibration: falling pressure
• Regulatory approvals: SIL2 according to IEC 61508-2
• Pressure type: relative overpressure
• Mounting type: pressure gauge connection
• For use with: chemical plants and process engineering
• Electrical connection: plug according to DIN EN 175301
• Connection type: internal thread G 1/4, external thread G 1/2