J. Kissel, D. Barker, J. Batch, J. Warner, S. Aston

Advised by J. Smith that LHO is suffering from Major-Carry transition glitching (LHO aLOG 17555), we've taken advantage of the front-end model restart chaos to re-calibrate the BSC SUS 18-bit DACs -- i.e. taken all front-end "user" processes (i.e. the SUS code) offline, and restarted the IOP process for the h1susex, h1susey, and h1susb123 front end computers / I/O chassis, which runs each chassis' DAC cards through their auto-calibration procedure. Those front ends include DACs for H1SUSETMX, H1SUSTMSX, H1SUSETMY, H1SUSTMSY, H1SUSITMX, H1SUSITMY and H1SUSBS.

Sadly, I realize while writing this entry, and after rereading Josh's entry (LHO aLOG 17555), that he says that it's the -2^16 transitions that are most of the glitches. Indeed, I even got an email I got from P. Fritschel today, en passant, reminding me that J. Betz and he have shown that the recalibration procedure does not reduce the -2^16 [ct] transition glitching (see G1401269). Hurumph.

Anyways, the re-calibration will at least help with the drift in glitchiness of the other two transitions ( 0 and +2^16 , potentially seen in, e.g. 16354).

I attach procedural notes that I gathered during the restart process (I learned quite a bit!)

P.S. There may be a "danger" that auto calibration of the 8th DAC (or DAC cardNum 7 if you count from zero) on the h1susb123, which house the control for the PUM on ITMX and ITMY, as the h1susb123 dmesg reports that the AUTOCAL failed for this DAC:
[6643729.576353] h1iopsusb123: 18-bit dac card on bus 36; device 4
[6643729.576367] h1iopsusb123: pci0 = 0xdfefe000
[6643729.576391] h1iopsusb123: dac pci2 = 0xdfefc000
[6643729.576398] h1iopsusb123: DAC I/O address=0xdfefc000  0xffffc90011b08000
[6643729.576403] h1iopsusb123: DAC BCR = 0x40000
[6643729.576427] h1iopsusb123: DAC BCR after init = 0x20040000
[6643729.576432] h1iopsusb123: DAC OUTPUT CONFIG = 0xff
[6643734.724703] h1iopsusb123: DAC AUTOCAL FAILED in 5133 milliseconds 
[6643734.724712] h1iopsusb123: DAC OUTPUT CONFIG after init = 0x102ff with BCR = 0x40000
[6643734.724719] h1iopsusb123: set_8111_prefetch: subsys=0x8111; vendor=0x10b5
I've confirmed that for every other DAC card (5 in EX, 5 in EY, and the other 7 on B123) we re-calibrated today, the dmesg claims success.