User's Manual
Table Of Contents
- 8 Parameter reference
- 9 Service and maintenance
- 10 Diagnosing and troubleshooting
- 11 Technical data
- 12 Dimension drawings
- 12.1 Threaded horn antenna
- 12.2 Threaded horn antenna with extension
- 12.3 Flanged horn antenna
- 12.4 Flanged horn antenna with extension
- 12.5 Flanged encapsulated antenna (2"/DN50/50A sizes only)
- 12.6 Flanged encapsulated antenna (3"/DN80/80A sizes and larger)
- 12.7 Threaded PVDF antenna
- 12.8 Threaded connection markings
- 12.9 Raised-Face flange per EN 1092-1 for flanged horn antenna
- 12.10 Raised-Face flange per EN 1092-1 for flanged encapsulated antenna
- 12.11 Flat-Face flange
- 12.12 Process connection tag (pressure rated versions)
- A Appendix A: Technical reference
- B Appendix B: HART communications
- C Appendix C: Certificates and support
- 13 List of abbreviations
- 14 LCD menu structure
- Glossary
- Index
Glossary
SITRANS LR250 (HART)
254 Operating Instructions, 01/2014, A5E32220602-AB
beam width
the angle diametrically subtended by the one-half power limits (-3 dB) of the microwave beam.
blanking
a blind zone extending away from the reference point plus any additional shield length.The
device is programmed to ignore this zone.
capacitance
the property of a system of conductors and dielectrics that permits the storage of electricity when
potential differences exist between the conductors. Its value is expressed as the ratio of a
quantity of electricity to a potential difference, and the unit is a Farad.
confidence
see Echo Confidence.
damping
term applied to the performance of a device to denote the manner in which the measurement
settles to its steady indication after a change in the value of the level.
dB (decibel)
a unit used to measure the amplitude of signals.
derating
to decrease a rating suitable for normal conditions according to guidelines specified for different
conditions.
dielectric
a nonconductor of direct electric current. Many conductive liquids/electrolytes exhibit dielectric
properties; the relative dielectric constant of water is 80.
dielectric constant (dK)
the ability of a dielectric to store electrical potential energy under the influence of an electric field.
Also known as Relative Permittivity. An increase in the
dielectric constant is directly proportional to an increase in signal amplitude. The value is usually
given relative to a vacuum /dry air: the dielectric constant of air is 1.