VF HF-50 - High Background Level; Fig. 58 Display - High Background Level

Troubleshooting
VF1807090083 EN revision 71
9.1. High background level
Fig. 58 Display – High background level
When measuring the background, the monitor continuously evaluates whether it is able to detect the required
surface activity corresponding to the surface activity alarm level (contamination signalling). If the background
response exceeds the limit where it is no longer able to detect the respective surface activity (not able to
signal the set surface activity alarm), the monitor is not able to measure.
If this state is reported by several detectors, there is probably a high background level in the place of the
monitor. It is necessary to ensure background reduction by removing the source if high background or to wait
until the background drops below the permitted limit or to move the monitor to a place with a lower
background.
If the state is reported by one detector, the given detector may be contaminated or damaged. The state of
high background level is indicated by a symbol appearing for the given detector; for consideration, the “ratio”
values may also be taken into account, see Chapter 6.4.2.