Wrong CRTT value in the output of 'wr_mon -e'
From Paul Boven (https://forums.ohwr.org/t/crtt-incorrect-on-wrs/849038):
Trying to do a full calibration between two switches, both running 6.0.1, and equipped with LJD and DWDM optics. Normally I would run ‘wr_mon -e’ for a while, so I can average over the CRTT values while using the different fiber lengths to measure the rx and tx delay of these optics. However, CRTT shows a suspiciously large value:
SERVO sv:1 ss:‘TRACK_PHASE’ md:2.967 dms:+0.000000002967 lock:1 dtxm:+0.000000238903 drxm:+0.000000275901 dtxs:+0.000000238903 drxs:+0.000000275901 crtt:18446744073708527942 setp:3370 asym:0.000 cko:0.002 ucnt:101
The CRTT seems to be a 64 bit number that has wrapped? It should however not be negative, given that when I take delay_MM (1035.542 ns) and subtract the dtxs, drxs, dtxm, drxm values, I still end up with a positive number of 5.934 ns, which matches the reported mean delay (md) above.