A new flag, named "CaliCheck", after a testing period, is now operative in the DMS, with that aim to prevent bad surprises in Calibration (as the Correction of 33% scaling factor event happened on last summer).
The flag monitors that the overall actuation gain/shape relevant for the calibration is within a standard range.
The used criterion is based on the amplitude of the TF Ca_xx_RM_CoilU / Sc_xx_zCorr at frequencies of the permanent calibration line (xx = NE, WE, PR, BS) around 35y.y Hz and at DARM loop frequency (379.0 Hz). The computation is performed online by AlpMoni and is a kind of LN1/HP ratio measurements.
In detail, for every coil:
- computes the ratio of the coil current (i.e. Ca_WE_RM_CoilU) over the correction signal (i.e. Sc_WE_zCorr) of the actuation DSP, at two above said frequencies;
- tots up the contribution of the 4 coils to get an average actuation gain at the two frequencies (the sum over the 4 coils has to be transparent to the use of 2 or 4 coils for the controls);
- in case of HP mode, uses a correction factor (LN1/HP) so that the ratio should be stable whatever the mode is;
- the computation is performed as soon as the permanent calibration lines and DARM line are switched ON;
- ratios are set to -1 during transition of the suspensions between different configurations (mode or number of coils);
- ratios are set to 0 if there is no coherence between the zCorr and the current.