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 140 SITRANS LR250 (HART) – INSTRUCTION MANUAL 7ML19985JE03
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D: Technical Reference
Loop power
Typical Connection Drawing
Allowable operating area of SITRANS LR250
Curve 1 (General Purpose, Intrinsically Safe, Non-incendive)
Loop Voltage versus Loop Resistance
Note: Loop voltage is the voltage at the terminals of the power supply (not the voltage
at the terminals of the device).
+
-
LR250
loop resistance
RL
loop current IL
loop voltage
VL
power
supply
Power Supply Requirements
0
100
200
300
400
500
600
700
800
900
15 17 19 21 23 25 27 29
Loop Voltage - V
L
(Source Voltage)
Loop Resistance - R
L
(30.0V, 845 ohms)
RL = 44.6 * VL - 493.4
(17.8V, 300 ohms)
(16.7V, 0 ohms)
RL = 272.7 * VL - 4554.1
Loop Voltage – V
L
Loop Resistance – R
L
ALLOWABLE
OPERATING AREA
Power Supply Requirements