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
7.4.1 Adjust the general threshold
If necessary, the general threshold value can be increased if a disturbance echo is
interpreted as the product surface. Alternatively, a lower threshold may be required to
handle weak surface echoes (e.g. due to excessive foaming or turbulence).
Prerequisites
The general threshold is set at factory for optimum performance and should not normally
need an adjustment.
Before changing the factory default value, study the position and amplitude of the
different echo peaks.
Procedure
1. Under
Menu, select Parameter → Advanced Setup.
2. In the General Threshold box, enter the desired value.
3. Select Write to device.
Related information
Analyze the echo peaks
General threshold
7.4.2 Change the upper null zone
The Upper Null Zone defines a zone close to the transmitter where echoes are ignored.
This zone can be extended to block out disturbing echoes at the top of the tank.
Prerequisites
Note
Make sure the Upper Range Value (100%/20 mA) value is below the Upper Null Zone.
Measurements are not performed within the Upper Null Zone.
Procedure
1. Identify desired Upper Null Zone by analyzing the echo peaks.
a)
Under Menu, select Diagnosis → Echo Peaks.
b) View the echo peaks to find out if there are disturbing echoes close to tank
top.
2. Set the desired Upper Null Zone value.
a) Under Menu, select Parameter → Geometry → Advanced.
b) Enter the desired Upper Null Zone value.
c) Select Write to device.
Service and troubleshooting Reference Manual
September 2020 00809-0100-4480
64 Rosemount 1408H Level Transmitter