Reference Manual
Table Of Contents
- Rosemount 1408H Level Transmitter
- Contents
- 1 Introduction
- 2 Transmitter overview
- 3 Mechanical installation
- 3.1 Safety messages
- 3.2 Installation considerations
- 3.3 Mounting preparations
- 3.4 Mount transmitter on tank
- 4 Electrical installation
- 5 Configuration
- 6 Operation and maintenance
- 7 Service and troubleshooting
- 7.1 Safety messages
- 7.2 Diagnostic messages
- 7.2.1 Device hardware fault – Device exchange
- 7.2.2 General power supply fault – Check availability
- 7.2.3 Device software fault – Check firmware revision
- 7.2.4 Parameter error – Check data sheet and values
- 7.2.5 Short circuit – Check installation
- 7.2.6 Device memory failure – Restore default settings
- 7.2.7 Level measurement lost – Check application
- 7.2.8 Simulation active – Check operational mode
- 7.2.9 Device temperature over-run – Clear source of heat
- 7.2.10 Device temperature under-run – Insulate device
- 7.2.11 Primary supply voltage over-run – Check tolerance
- 7.2.12 Primary supply voltage under-run – Check tolerance
- 7.2.13 Maintenance required - Cleaning
- 7.3 Troubleshooting incorrect level readings
- 7.3.1 Reported level is too high or low
- 7.3.2 Level is stuck in measuring range
- 7.3.3 Level is stuck in full tank
- 7.3.4 Level value drops when close to antenna
- 7.3.5 Measured level fluctuates
- 7.3.6 Measured level is occasionally unstable
- 7.3.7 Lagging of measured level
- 7.3.8 Incorrect level at 100% (20 mA)
- 7.3.9 Incorrect level when product surface is above 50%
- 7.3.10 Dropping of level close to tank bottom
- 7.3.11 Level measurement is lost in an empty tank
- 7.3.12 Alarm mode close to tank bottom
- 7.4 Managing disturbance echoes
- 7.5 Service and troubleshooting tools
- 7.6 Service support
- A Specifications and reference data
- A.1 Performance specifications
- A.2 Functional specifications
- A.3 Physical specifications
- A.4 Dimensional drawings
- B Product certifications
- C Configuration parameters
7.3.12 Alarm mode close to tank bottom
Symptom
When the product surface is near the sloped tank bottom, the transmitter enters alarm
mode.
Figure 7-12: Symptom
A
B
C
D
A. Level
B. Time
C.
Actual level
D. Reported level
Possible cause
Reduction of projected surface area close to sloping tank bottom.
Recommended actions
• Verify the tank geometry parameters are configured correctly (especially the
Reference Height and Bottom Offset).
Related information
Reference height
Bottom offset
7.4 Managing disturbance echoes
There are two general methods for managing disturbance echoes:
• Set general threshold to filter out weak disturbance echoes and noise.
• Increase the Upper Null Zone to block out disturbance echoes at the top of the tank.
Reference Manual Service and troubleshooting
00809-0100-4480 September 2020
Reference Manual 63