#linuxcnc-devel Logs

Jan 01 2020

03:04 PM skunkworks: pcw_home: you around?
03:08 PM skunkworks: so running the 2 inch distance every servo cycle - No dpll and I get a variance of 1.7187 and 2.28125 on my first run
03:08 PM skunkworks: it stalls
03:08 PM skunkworks: after a while
03:08 PM skunkworks: 500hz servo cycle
03:08 PM skunkworks: following error of about .0005
03:10 PM skunkworks: no packet errrors
03:16 PM skunkworks: so - if I did the math right - it is a period variation of 2.333ms to 1.75ms
03:16 PM skunkworks: so far
03:41 PM pcw_home: Its a fairly subtle issue because you may have the much variation from cycle to cycle but the average should be 2.00 ms
03:42 PM pcw_home: so you may need to put the timing result through a low pass filter to see any shift
06:37 PM Tom_itx is now known as Tom_L
09:02 PM skunkworks: pcw_home: like if the average stays too far in one direction? Like the average isn't 2ms?
09:34 PM pcw_home: yes or shifts suddenly
09:42 PM Tom_L: pcw_home, you ever use the clocking wizard in ise?
09:49 PM pcw_home: No, I haven't
09:51 PM Tom_L: do you know if the onboard pll can multiply clock signals?
09:52 PM Tom_L: spartan6
09:56 PM pcw_home: I have only used the DPLL (which can do N/M frequency multiplication/division)
10:02 PM Tom_L: ok