User's Manual
Table Of Contents
- Table of Contents
- SITRANS LR250 Overview
- Specifications
- Installation
- Wiring
- Operating via the handheld programmer
- Operating via SIMATIC PDM
- Functions in SIMATIC PDM
- Quick Start Wizard via SIMATIC PDM
- Changing parameter settings using SIMATIC PDM
- Parameters accessed via pull-down menus
- Operating via AMS Device Manager
- Functions in AMS Device Manager
- Features of AMS Device Manager
- Device Description (DD)
- Configuring a new device
- Startup
- Pull-down menu access
- Device configuration
- Quick Start Wizard via AMS Device Manager
- Maintenance and Diagnostics
- Remaining Device Lifetime [see Remaining Device Lifetime (4.2.) on page 99]
- Remaining Sensor Lifetime [see Remaining Sensor Lifetime (4.3.) on page 102]
- Service Schedule [see Service Schedule (4.4.) on page 105]
- Calibration Schedule [see Calibration Schedule (4.5.) on page 108]
- Electronic Temperature
- Wear (see Wear on page 56)
- Communication
- Security
- Device Diagnostics
- AMS Menu Structure
- Functions in AMS Device Manager
- Parameter Reference
- 1. Quick Start
- 2. Setup
- 3. Diagnostics
- 4. Service
- 5. Communication
- 6. Security
- 7. Language
- Appendix A: Alphabetical Parameter List
- Appendix B: Troubleshooting
- Appendix C: Maintenance
- Appendix D: Technical Reference
- Principles of Operation
- Echo Processing
- Analog Output
- Maximum Process Temperature Chart
- Process Pressure/Temperature derating curves
- Loop power
- Appendix E: Application Examples
- Appendix F: HART Communications
- Appendix G: ATEX Certificates
- Appendix H: Firmware Revision History
- Glossary
- Index
- LCD menu structure
Page 128 SITRANS LR250 (HART) – INSTRUCTION MANUAL 7ML19985JE03
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D: Technical Reference
Center
Uses center of the echo.
Hybrid
Uses the Center algorithm for the top part of the vessel, and the CLEF algorithm for the
part nearest the vessel bottom, according to the setting for CLEF range.
CLEF (Constrained Leading Edge Fit)
• Uses the leading edge of the echo.
• Is used mainly to process the echo from materials with a low dK value.
In an almost empty flat-bottomed vessel, a low dK material may reflect an echo weaker
than the echo from the vessel bottom. The echo profile shows these echoes merging. The
device may then report a material level equal to or lower than empty
The CLEF algorithm enables the device to report the level correctly.
Example: CLEF off: Position set to Hybrid
default TVT
vessel
bottom
echo
selected
material
echo
echo marker
Vessel height: 1.5 m; CLEF range set to 0 (Center algorithm gives the same result.)