Table of Contents
Advertisement
10.5
Measurement difficulties
If the LOE Timer (2.4.2.) (Page 177) expires due to a measurement difficulty, the mA Fail-
safe Value (2.4.9.) (Page 180) displays. In rare cases, the device may lock on to a false
echo and report a fixed or wrong reading.
10.5.1
Loss of Echo (LOE)
The mA Fail-safe Value (2.4.9.) (Page 180) displays [seen in Milliamp Output (2.5.9.)
(Page 182)] when the echo confidence is below the threshold value set in Long Echo
Threshold (2.11.2.3.) (Page 223).
LOE occurs when:
● The echo is lost and no echo is shown above the ambient noise. See confidence [Long
Confidence (3.2.11.2.) (Page 262) and Short Confidence (3.2.11.3.) (Page 262)] and
echo strength [Echo Strength (3.2.11.4.) (Page 263)].
● Two echoes are too similar to differentiate (when BLF Best F-L algorithm is used). See
confidence [Long Confidence (3.2.11.2.) (Page 262) and Short Confidence (3.2.11.3.)
(Page 262)] and echo strength [Echo Strength (3.2.11.4.) (Page 263)].
● No echo can be detected within the programmed range.
If mA Fail-safe Value (2.4.9.) (Page 180) is displayed, ensure the following conditions:
● Surface monitored is within the transducer maximum range.
● Transducer (2.1.5.) (Page 164) matches the transducer used.
● Transducer is located and aimed properly.
● Transducer that has no submergence shield is not submerged.
10.5.1.1
Adjust transducer aiming
See the transducer manual for range, mounting, and aiming details. For optimum
performance, adjust transducer aiming to provide the best Long Confidence (3.2.11.2.)
(Page 262) and Echo Strength (3.21.11.4.) (Page 263) for all material levels within the
measurement range.
Displaying echoes
Check for echoes remotely using SIMATIC PDM.
10.5.1.2
Increase fail-safe timer value
Increase the LOE Timer (2.4.2.) (Page 177) value if fail-safe operation will not be
compromised by doing so. Try this only if LOE exists for short periods of time.
HydroRanger 200 HMI
Operating Instructions, 06/2018, A5E36281317-AC
Diagnosing and troubleshooting
10.5 Measurement difficulties
289
Advertisement
Table of Contents
Troubleshooting
