Fixed Reading - Siemens HydroRanger 200 HMI Operating Instructions Manual

Fixed reading

If the reading is a fixed value, regardless of the transducer to material surface distance,
ensure the following conditions:
1. Transducer acoustic beam is free from obstruction.
2. Transducer is properly aimed.
3. Transducer is not in contact with any metal object.
4. Material mixer (if used) and the HydroRanger 200 HMI are operating at the same
time. If it the mixer is stopped, make sure that the blade is not stopped under the
transducer.
Obstructions in the sound beam
Check for (and remove, if present) any acoustic beam obstruction, or relocate the
transducer.
If an obstruction cannot be removed or avoided, adjust the Time Varying Threshold (TVT)
curve to reduce the Echo Confidence derived from the sound reflected by the obstruction.
Use SIMATIC PDM to adjust the TVT curve.
Nozzle mountings
If the transducer is mounted on or in a nozzle: grind smooth any burrs and welds on the
inside or open end (the end that opens into the vessel). If the problem persists, install a
larger diameter or shorter length nozzle, bevel the inside of the bottom end, or cut the
open end of the nozzle at a 45° angle.
See the transducer manual for complete mounting instructions.
If the mounting hardware is overtightened, loosen it. Overtightening changes the
resonance characteristics of the transducer and can cause problems.
Set the HydroRanger 200 HMI to ignore the bad echo
If the preceding remedies have not fixed the problem, the false echo has to be ignored.
If the echo is close to the transducer
If there is a static, incorrect high level reading from the HydroRanger 200 HMI, there is
probably something reflecting a strong echo back to the transducer. If the material level
never reaches that point, extend the
obstruction.
Adjust the TVT to ignore the echo
2. 1 1.3.2. Auto False Echo Suppression
Use
TVT Shaper
to manually shape around false echoes.
A5E36281317
2.2.6. Blanking
HydroRanger 200 HMI – OPERATING INSTRUCTIONS
to a distance just past the
. If this does not correct the problem, use
2. 1 1.4.
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