User's Manual

Table Of Contents
7ML19985JM01 SITRANS LR 460 – INSTRUCTION MANUAL Page 53
mmmmm
Profile structure
Description of the blocks
Transducer block function groups
The figure below shows the signal flow of measured values from the sensor through the
Transducer block into the output value (Primary Value/ Level or Volume; Secondary Value
1 / Level; Secondary Value 2 /Distance 1; or Secondary Value 3 / Distance 2). The Level TB
implements all of the basic parameters (see parameter diagram on page 54), including
level to volume calculation, if that option has been selected.
How the LTB works:
1. The sensor technology block selects the proper echo. For an explanation of sensor
technology, please refer to
Appendix B: Technical Reference
, page 82 onwards.
The sensor value (in sensor units) is checked to see if it is within its measuring limits.
If the limit is exceeded, this results in a Bad status and the error message Failure in
measurement. The sensor value is stored in Sensor Value.
The analog signal from the sensor is transformed into a digital signal.
A Sensor Offset (default 0) provides compensation if necessary for changes in the
sensor.
Level Transducer Block
Sensor Value
Sensor
Sensor
technology
Level
calibration
Linearization
Level
Primary Value
[Level/Volume]
(level/volume units)
(Analog
Input)
AIFB1
Secondary Value 1
[Level]
(Level Units)
Secondary Value 2
[Distance 1]
(Sensor Units)
Sensor
Offset
Level
Offset
High
Calibration
Point
High Level
Point
Low
Calibration
Point
Low Level
Point
Calibration
Type
Linearization
Type
Secondary Value 2
[Distance 2]
(Level Units)
Sensor
Level unit
conversion
PV
SV1
SV2
SV3
AIFB2
(Analog
Input)