Siemens SITRANS LR 400 Instruction Manual page 35

3.3.2: Simulate DO (F = End)
Simulation of the digital output signal
Value
Select the applied output value "Relay on" or "Relay off" .
The function is ended after pressing
limit.
3.4: Sensor Variables
You can read out device-internal data with this function. The displayed values depend on
the respective application. You can access the following data:
3.4.1: Raw Value (for service purposes only)
Distance from the flange to measuring medium
The measured distance from the flange to the surface of the measuring medium.
3.4.2: Echo Amplitude
Measure of quality of reflection
This dimensionless value is an absolute measure of the strength of reflection at the
measuring medium. Its display can be evaluated as follows:
• x > 1: very good
• 1 > x > 0.5: good
• 0.5 > x > 0.05: satisfactory
• x < 0.05: uncertain
3.4.3: S/N Ratio
Signal-to-noise ratio of the measured value in dB
S/N Ratio provides a relative measure of the strength of reflection of the measuring
medium in dB. Its display can be evaluated as follows:
• x > 20: very good
• 20 > x > 10: good
• x < 10: satisfactory
7ML19985FH01
Relay on
Relay off
End
SITRANS LR 400 – INSTRUCTION MANUAL DRAFT
so that the digital output again gives an alarm/
Page 31