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Hazardous Area Proximity Sensors

TURCK 6/7/2018
TURCK NAMUR proximity sensors are 2-wire sensing devices meeting the interoperability requirements of EN 60947-5-6. Because NAMUR sensors operate on very low power, they can be designed to be intrinsically safe for use in hazardous locations. Turck NAMUR compliant sensors have intrinsic safety approval from FM, CSA, ATEX and others.

The operation of NAMUR sensors is similar to that of a variable resistor, with a change of impedance as a target approaches the sensor. When no metal is being sensed, an inductive sensor is in a low impedance state and draws a current of more than 2.2 mA. When a metal target enters the high-frequency field radiated from
the sensor face, the impedance increases as the target approaches. When fully damped, the sensor draws less than 1.0 mA.  This current change is used to trigger an external amplifier at a defined switch point, usually about 1.5 mA.

Hazardous Area Proximity Sensors

NAMUR sensors contain a relatively small number of components, which allows the construction of small devices and helps to ensure a high degree of reliability.  As the sensors are 2-wire current loops with fairly low impedance, they are unaffected by most transients.

General NAMUR Specifications

Differential Travel (Hysteresis):  1-10% (5% typical)
Nominal Voltage:  8.2 VDC (EN60947-5-6)
Resistance Change from
Nonactivated to Activated Condition:  typical <1.0 to >8.0 kΩ
Resulting Current Change:  ≥2.2 mA to ≤1.0 mA
Recommended Switching Point
for Remote Amplifier:  >1.2 to <2.1 mA, typ. 1.55 mA ON/1.75 mA OFF
Power-On Effect:  Realized in Amplifier
Reverse Polarity Protection:  Incorporated
Wire-Break Protection:  Realized in Amplifier
Transient Protection:  Realized in Amplifier
Shock:  30 g, 11 ms
Vibration:  55 Hz, 1 mm Amplitude in all 3 Planes
Repeatability:  ≤2% of Rated Operating Distance

See TURCK Sensors Catalog for detailed individual specifications for all NAMUR sensors.

Hazardous Area Proximity Sensors

TURCK NAMUR proximity sensors are functionally compatible with all switch amplifiers with input characteristics that meet the NAMUR requirements. Their approved intrinsic safety entity parameters are compatible with all TURCK safety switch amplifiers and remote I/O systems.  See Section B, IS Interface Technology, and Section C, IP 20 Slice I/O, for more information.

Class I, Division 2 Hazardous Area Sensors

TURCK 3-wire DC proximity sensors with code AN6., AP6., RN6., or RP6. with threaded barrels are approved by FM Approvals for installation in Class I, Division 2 hazardous locations.  The sensors must be installed using a Division 2 wiring method, which, for all practical purposes, means that the sensor must be either installed in an enclosure that requires the use of a tool to open, or they must be adapted to a raceway or conduit product. TURCK TMF conduit adapters or other suitable thread adapters may be used for this purpose.

Hazardous Area Proximity Sensors

Conduit Adapters

When installed in this fashion and powered from a supply not exceeding 30 VDC, there are no further energy limiting or protective enclosure requirements for installation in Class I, Division 2.  The sensors have no arcing or sparking components and will not dissipate heat under normal operating conditions.
Part Number ID Number Barrel Diameter Dimensions
TMF 12-G A3310 12 mm 1.15 [29.2] 1.00 [25.4] 1.00 [25.4] 0.50 [12.7] 0.50 [12.7] M12x1
TMF 18-G A3320 18 mm 1.15 [29.2] 1.00 [25.4] 1.00 [25.4] 0.50 [12.7] 0.50 [12.7] M18x1
TMF 30-G A3345 30 mm 1.73 [44.0] 1.50 [38.1] 1.00 [25.4] 0.60 [15.2] 0.40 [10.2] M30x1.5
Use above Conduit Adapters with G and P Barrel sensors.
TMF 18-MS A3330 18 mm 1.15 [29.2] 1.00 [25.4] 2.00 [50.8] 1.50 [38.1] 0.50 [12.7] M18x1
TMF 30-MS A3355 30 mm 1.73 [44.0] 1.50 [38.1] 2.00 [50.8] 0.60 [15.2] 1.40 [35.6] M30x1.5
Use above Conduit Adapters with M and S Barrel sensors.
Hazardous Area Proximity Sensors
Material: Aluminum
Inches [mm]