KROHNE LEVEL-SONIC BM90 Series Installation And Operating Instructions Manual page 35

N O T E: The sensor sensor compensates only for tem-
perature variance, it is not expected to accurately
measure the actual temperature.
P) The boards hums loudly:
* Usually vibration from the transformer.
1. Check the mounting screws for tightness.
Q) Relays not switching:
1. Check the programmed relay designations and settings
at Pr.8 - Pr.22 Functions can be tested under simulation
using Pr.78.
2. Test the actual relays using Pr.75 or Pr.76.
3. Check contact continuity at the terminals 4 - 18.
WARNING: It is reccomended that all external con-
trols, alarms etc. are disconnected before performing
the above tests.
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