Namur Standards

This came up recently at work and I am not sure as I don't entirely understand the differences myself.

http://www.namur.de/start/?L=2

It looks like some form of engineering association specifically for companies so they can mark their products with the Namur name to indicate they are of good quality (like marking that the company has ISO9000 approval).

Someone here in the process control or instrumentation area may have more experience.

I wondered, too, about NAMUR and had a very short talk (language barriers) with a couple of Germans manning a NAMUR booth at a national ISA show several years ago. All they could tell me was that it was a collaborative effort between process instrument user groups, international but primarily Western European in reality, to define working standards for users of process instrumentation.

Over the years, I have encounterd NAMUR in 4 areas:

1) NAMUR Standard NE 043 Sensor Error Response
Defines the signal levels which sensors output when diagnostics detect a fault.
example: Rosemount 2090P absolute pressure transmitter has two NAMUR options:

that perform in this fashion, compared to non-NAMUR response:

2) Direct Mount solenoid valves on process valves:

A NAMUR standard allows solenoid valves (ASCO) used on modulating process valves to be direct mounted.

Standard 3-way and 4-way solenoid valves' NPT pipe connections and mounting configurations have been replaced by NAMUR mounting configuration. This allows the valve to be mounted directly to an actuator.

3) Intrinsically safe prox switches on valves
Pepperell & Fuchs has NAMUR IS prox switches used by numerous valve manfacturers.
I seem to recall that the 2 wire proxes have definable fail mode states, as well as the expected binary on-off states, but I don't have a reference for that.

4) Extensive diagnostics in field instruments based on studies by NAMUR

User studies of field faults has lead to extensive diagnostics in field instruments.

Example: Krohne's Magmeters have several dozen diagnostics related to common failure modes in magmeters. Krohne's white paper that cites the NAMUR points is at
http://www.krohne.com/fileadmin/media-lounge/PDF-Download/Diagnose_in_OPTIFLUX_e.pdf

Take a look on this site:

http://www.tektron.ie/namur1.htm