Berthold DUO XPERT LB 470RID, Operating Manual

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3 System Description LB 470RID Level
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56925-1BA2 Rev.02, 05/2021
3.3.5 Automatic Calibration Improvement
For an optimum recognition of interference radiation and reliable switching from
Measuring to Secondary Channel, the level must be measured exactly equally in
both channels under normal operating conditions without interference radiation,
i.e. the channel difference should be near zero.
Deposits on the vessel walls, high voltage variations, Photomultiplier and scintilla-
tor ageing, have different effects on each channel. Errors between channels could
therefore increase after some operating period leading to false level determina-
tions and degradation of the interference suppression function. This would surface
as false radiation interference readings. To avoid this, the system includes auto-
matic compensation.
For this reason, it is inevitable to constantly balance the levels measured in both
channels and to minimize the channel difference during normal operation. The
LB 470RID system therefore has an integrated automatic channel difference mini-
mization function. As a result, the above influences are compensated and the
function of the interference radiation suppression is maintained even after a long
period of operation.