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)
258 Operating Instructions, 01/2014, A5E32220602-AB
repeatability
the closeness of agreement among repeated measurements of the same variable under the
same conditions.
sensor value
the value produced by the echo processing which represents the distance from sensor reference
point to the target. (see
Sensor Mode (2.2.2.)
for an illustration).
shot
one transmit pulse or measurement.
speed of light
the speed of electromagnetic waves (including microwave and light) in free space. Light speed is
a constant 299, 792, 458 meters per second.
stilling-well
see stillpipe.
stillpipe
a pipe that is mounted inside a vessel parallel to the vessel wall, and is open to the vessel at the
bottom.
TVT (Time Varying Threshold)
a time-varying curve that determines the threshold level above which echoes are determined to
be valid.
two wire radar
a low-energy radar. Can be loop powered, analog, intrinsically safe 4 to 20 mA, or a digital
(BUS) transmitter.
waveguide antenna
a hollow, metallic tube that transmits a microwave signal to the product target.