#linuxcnc-devel Logs

Dec 11 2019

06:15 PM skunkworks: adding a shield to the ribbon cable didn't help
06:33 PM skunkworks: burklefoo: could you make me a 7i92_mx3660_ssed.bit with input filtering to try?
08:07 PM skunkworks: jepler: burklefoo: http://electronicsam.com/images/greenmachine/IMG_20191211_200010.jpg
08:12 PM burklefoo: skunkworks: which pins are inputs?
08:33 PM burklefoo: (because if you enable the INM it will claim all its pins)
09:24 PM skunkworks: hmm - let me look
09:27 PM skunkworks: burklefoo:
09:27 PM skunkworks: net xhome joint.0.home-sw-in hm2_7i92.0.gpio.016.in
09:27 PM skunkworks: net yhome joint.1.home-sw-in hm2_7i92.0.gpio.014.in
09:27 PM skunkworks: net zhome joint.2.home-sw-in hm2_7i92.0.gpio.015.in
09:28 PM skunkworks: and 016 seems to be the only one with noise..
09:28 PM skunkworks: which is odd
09:29 PM skunkworks: but like I say - if I use a normal female to female printer cable - the problem goes away.
09:29 PM skunkworks: Do they do some funny twisting?
09:29 PM skunkworks: every signal gets twisted with a ground?
10:01 PM burklefoo: yes all wires in IEEE-1284 have a ground pair
10:03 PM burklefoo: it may be more likely that the noise is from a ground loop than from pickup (and the IEEE-1284 cable has much lower ground impedance than flat cable)
10:03 PM burklefoo: (because of all the ground wires and shield)
10:15 PM skunkworks: I would have to say the sheild I connected at both ends was substantial..
10:16 PM skunkworks: (and I then unhooked one end with no change)