J. Kissel, R. Kumar, O. Patane, F. Clara

We're debugging why high-frequency asymptote/slope/frequency response of PM1's transfer functions do not match RM1's -- see RED (PM1) and BLACK (RM1) from the attachments of LHO:84397.
I immediately suspected coil driver compensation filters in COILOUTF banks did not match the analog HAM-A driver's low pass filter *state.* 
In the modern era all HAM-A driver's low pass filters are to be jumpered ON since we don't have binary input/ouput remote control of them. And when instantiating a new HTTS suspension, because there's no MEDM interface to set it, and you have to "caput" the channel (H1:SUS-RM1_BIO_M1_STATEREQ) to 2.0 via the command line. 
When we forget to do this, we errantly see the analog response of the driver in the health check transfer functions rather than the expected "falls as 1/f^2 above the resonances."

We confirmed (via trend) that I *did* set this correctly when I original brought the infrastructure online see LHO:84457 comment to LHO:83293 on Mar 20 2025. 
We also confirmed that it's still the case today -- see attached screenshot, with magneta box around the CD state.

We also confirmed that the LED status lights of the LP filter are green / ON, which report that, internally, indeed the HAM-A driver's LP filter switch is in the "Run" state, which is LP ON, see attached photo of SUS-C4, U-heights 3 (for PM1),4 (for RM2), 5 (for RM1) (per page 14 of D0902810-v11).

HOWEVER 
(1) In taking that picture, I noticed that all the HAM-A drivers in that rack had a sticker mentioning ECR E2100430 *except* for PM1's driver in U3. 
In that ECR -- which is for modifying the OMs -- is better described in T2100410, the low pass filter response was changed from a z:p = [10,20]:[1,200] to z:p = [0.5,3174]:[52.32, 50.77].
There are later ECRs E2200307 and E2400048 that demand the *rest* of the HAM-A drivers should be modified with these same changes.
Tickets IIET:20650 (for OMs) IIET:24501 (for IMs, RMs, and OFI), confirm that these modifications have been done at LHO for those suspensions.

(2) IIET:30349 (for the A+ SUS), suggests that no such modifications have been done at LHO (and partially implemented at LLO).
Rahul confirms with a pictures from SUS-M1 that the ZM1 ZM2 ZM3 and the OPO, and SUS-C8 for ZM4 ZM5 ZM6 that there are no stickers referencing any ECR E2100430, E2200307, and what it *should* reference, E2400048.
From this we conclude that E2400048 has NOT been implemented here at LHO.
 
(3) Finally - even though ECRs demand that essentially ALL HAM-A drivers should now have this LP filter change -- there exists NO version of D1100117 that has the the change in components or callout of new frequency response. This is likely why this change got overlooked when setting up PM1's HAMA driver.

So, from the lack of sticker, lack of updated circuit drawing, and odd health check transfer function response --  we conclude frequency response PM1's HAM-A driver has frequency response is still the z:p = [10,20]:[1,200] response.

When I set up PM1, I copied RM1's COILOUTF frequency response. 
RM1's COILOUTF is *correctly* was compensating the z:p = [0.5,3174]:[52.32, 50.77] analog response. 
However, that will NOT correctly compensate the unmondified PM1 driver's z:p = [10,20]:[1,200] response.

*sigh* For now, we'll update the COILOUTF filters, and then discuss later when / if we want to modify the driver.