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
Upper null zone
The Upper Null Zone defines how close to the transmitter's reference point a level value is
accepted. You can extend this value to block out disturbing echoes close to the antenna,
for example from the tank nozzle.
Note
Make sure the 20 mA value is below the Upper Null Zone. Measurements are not
performed within the Upper Null Zone (UNZ).
Related information
Change the upper null zone
Bottom offset
The Bottom Offset is defined as the distance between Zero Level and the tank bottom. The
default value is zero.
If the Zero Level is not located at the tank bottom, then enter a Bottom Offset. It is needed
for the transmitter to know the position of the tank bottom.
Figure C-10: Bottom Offset
A
B
C
D
+
A. Device Reference Point
B. Reference Height
C.
Zero Level
D. Bottom Offset
Negative level
If Bottom Offset is greater than zero, the level value can be negative. This parameter
determines if the shown level value can be negative or zero.
Reference Manual Configuration parameters
00809-0100-4480 September 2020
Reference Manual 93