J. Kissel, K. Arai

After Arnaud and Fil graciously debugged the binary I/O for the H1 SUS OMC (see LHO aLOG 8563), I began and finished a round of DTT transfer functions to clear the suspended dynamics. While the frequency dependence looks great and as expected, there appears to be an anomalous scale factor of 5.5 in all degrees of freedom. Since the scale factor is identical in all degrees of freedom it implies something is Arai (teehee, couldn't resist) with the electronics or digital chain and not something inherent to the dynamics.

As such, I've vetted the digital portion of the chain:

- Measurement calibration factor (i.e. post-processing measurement analysis)
    - L1 uses 0.26193 [(m/ct) / (N/ct)] (see, e.g., LLO aLOG 9570) -- is the same as used here to calibrate this measurement, and L1's measurements match the model well (certainly not off by a factor of 5.5). Therefore the post-processing scale factor is the same (It's not that we forgot the 18 vs. 16 bit DAC factor of 4 or that we have the wrong coil driver transconductance or coil-magnet gain compensation, etc.).
    - (Not attached, but) I made the same plots but dividing the measurement by a further factor of 5.5 (exactly, which is how I got the number), and the measurements line up with L1's measurements excellently, and which all match the model to within ~1.0%.

- EPICs Values
    - The OSEMINF Calibration Filters ("to_um") are turned ON (and the maltab processing code has meas.sensCalib = true)
    - OSEM2EUL and EUL2OSEM matrices are as produced by make_susomcs_projections.m, which is what L1 uses to install their matrices.
    - No excess gain in the SENSALIGN matrix; an identity matrix as expected
    - No excess gains in the TEST filters
    - The OSEM sensor normalization gains in the OSEMINF bank are roughly 1.3 to 1.4, as expected, no gains close to 5.5
    - The COILOUTF filter magnet polarity gains are +/- 1.0 as expected
    - The DRIVEALIGN matrix is no longer in the TEST excitation path, so that can't screw us up 

- Foton Filters
    - The OSEMINF filters have the expected DC gain (10:04 has a DC gain of 1.0, "to_um" has a DC gain of 0.02333)
    - The COILOUTF filters are all engaged and all have a DC gain of 1.0
    - The DAMP filters are not installed, but they're inconsequential to this undamped measurement


In summary, I confirmed that everything digital in the transfer function path is OK, and I confirmed that all post-processing is identical. So -- I've been wrong that it wasn't a digital problem once already this evening, but -- I don't see anything that could be wrong other then the analog electronics chain. We'll investigate more tomorrow morning.

If we're really pressed for time (i.e. we must install tomorrow or man-power to install evaporates) -- after we install the damping filters (quick), and get a set of damped transfer functions (1.5 hours), I vote we punt debugging this until after install. Unless anyone knows of something obvious...