NAMUR sensor
The NAMUR sensor (according to NAMUR - standards working group for measurement and control technology in the chemical industry) was first defined in the NAMUR worksheet NA01, which was transferred to DIN EN 60947-5-6 (VDE 0660-212: 2000-12) in 2000 has been. The NAMUR worksheet NA01 has been withdrawn since 2002.
Sensors according to NAMUR represent binary information and are usually designed as proximity switches, i.e. H. the sensor indicates whether or not a reference object (e.g. a stop on a moving machine part) is in the vicinity and often works without contact. Often inductive methods are used, one then speaks of a damped sensor (sensor recognizes the reference object or is "at the stop") or an undamped sensor (reference object is not recognized, sensor is not "at the stop").
NAMUR sensors are operated with an impressed current and have four states , so that sensor errors can also be recognized by an analog evaluation unit.
With normally open contact (NO) With normally closed contact (NC) 1. Current of 0 mA ⇒ Wire break , circuit open ⇒ Wire break , circuit open 2. Current below 1.2 mA ⇒ Sensor ready, undamped ⇒ Sensor ready, damped 3. Current greater than 2.1 mA ⇒ Sensor ready, damped ⇒ Sensor ready, undamped 4. Current of maximum value ⇒ short circuit , maximum current ⇒ short circuit , maximum current
In this context, one also speaks of the closed- circuit current principle .
The operating voltage of the field loop should be 8 ± 1 volts, the load in the event of a short circuit between 100 and 360 ohms.
A widespread application for NAMUR sensors or NAMUR initiators are limit switches for automated control valves.
The following circuit can help to simulate NAMUR sensors, e.g. for test purposes.
The contact shown can be any switch or button. Commercially available resistors can also be used.
Individual evidence
- ↑ NAMUR: Note on NAMUR worksheet NA01. In: NAMUR. NAMUR, September 6, 2002, accessed December 1, 2017 (en / de).