NE 131 has been revisedfrom 2017-10-16
The document differs from NE 131 edition 2009-04-29 beside editorial adjustments as follows:
- New title
- Section on requirements restructured
- Device parameter requirements added
- Annexes on device parameters with tables added
- Requirements to be met by the NAMUR standard device specified as operating function and as safety instrumented function
- Table with standard overall length data of flow meters added
Abstract NE 131 ‘NAMUR standard device – Field devices for standard applications’
The development of field devices in recent decades has been influenced by the introduction of new measurement principles for industrial applications and the innovative use of microelectronics in field devices. As a consequence, users in the process industry can, in addition to new methods, avail of familiar measuring procedures with improved and expanded device functionality.
Field device manufacturers have to date continually increased the number of device functions they offer and, indeed, continue to do so. These additional functions, which exceed the ambit of the actual measuring task involved, make devices interesting and can considerably expand the application scope of a device in an individual case. However, additional device costs are generally involved here which must be borne when the additional functions are not used. Experience gained in practical applications indicates that the additional functions are not utilised in the overwhelming majority of application cases.
A field device design is presented in this revised NAMUR recommendation which is suitable for 80% of application cases in operating functions and safety instrumented functions as well. The requirements of such a field device are described in detail. Additionally the most important device parameters and their default values are defined. These so-called NAMUR standard device parameters allow quick commissioning and device replacement. User aspirations are covered by this device series for the normal or “standard“ application case, i.e. users get only the specific device functionality specifically required. Manufacturers and users profit from the concentration on important device characteristics for the ”mass market“ and the NAMUR standard device series created for this purpose. The increased level of standardisation reduces the diversity of types and enables the production of higher quantities. This results in additional potential for cost reduction.
The requirements for field devices for standard applications in the process industry from the point of view of the user are formulated in this NAMUR recommendation. The development of a “NAMUR standard device“ series is initiated in this context, with device characteristics being reduced to a minimum while still covering 80% of application cases.