User's Manual

Appendix A: Technical reference
A.3 Analog Output
SITRANS LR250 (HART)
Operating Instructions, 01/2014, A5E32220602-AB
225
A.3.1
Sensor Mode
This parameter controls the input. Depending on the reference point used, the measurement
reports either Level, Space, or Distance. By default Sensor Mode is set to
Level
.
Operation
Description
Reference point
NO SERVICE Measurement and associated loop current
not being updated. Device defaults to Fail-
safe mode
a)
.
LEVEL Distance to material surface Low Calibration Point (process
empty level)
SPACE Distance to material surface High Calibration Point (process
full level)
DISTANCE
Distance to material surface
Sensor reference point
a)
See Fail-safe Mode (Page 227).
You also have the option to put the device out of service, in which case the device defaults to
Fail-safe mode, and the reported level depends on the device type. A standard device reports
the last valid reading, and a NAMUR NE 43-compliant device reports the user-defined value for
Material Level (3.58 mA by default).
①
Sensor reference point
⑤
4 mA 0%
②
High calibration point
⑥
Distance
③
20 mA 100%
⑦
Level
④
Space
⑧
Low calibration point