Siemens MOBILETT Plus Manual page 39

Filament circuit
The fixed values are only used when there is no table with adapted values. In that case,
the table with fixed values is copied into the table for adapted values.
Later the table will be adjusted and optimized to correspond to the individual generator
and X-ray tube.
In preparation mode, the signal "FIL VAL" must comply with three conditions in order to
avoid an error message:
1.
2.
3.
Fig. 2
Siemens-Elema AB
Solna, Sweden
The voltage level of the signal "FIL VAL" must be within a certain tolerance
range.
A filament current reference is derived from the adapted pulse-width value for
the selected kV value.
Due to the individual differences in the filament current characteristic within the
X-ray tube series used in the single tank, the tolerance for "FIL VAL" is defined
to be ±0.6 V.
The voltage level of the signal "FIL VAL" must be stable.
The voltage level of the signal "FIL VAL" is measured during a time of 3 s
maximum, periodically every 13 ms. If the difference between two consecutive
values for all of the last 20 values measured is <0.1 V, the signal "FIL VAL" is
regarded as stable.
As soon as the stability of the voltage level of "FIL VAL" is verified, the current
voltage level of "FIL VAL" is assigned as the new reference value.
The filament program then changes to the "holding mode".
In this mode the signal "FIL VAL" must remain within the tolerance range of
±0.12 V, relative to the reference value.
Tolerance range in
preparation mode 0.6 V
Tolerance range in
holding mode 0.12 V
Register 6 SPR8-215.850.02
Rev. 01 01.02
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