I tried to find the original message in previous monster thread to have a better understanding of the problem but could not find it. I can't remember seeing what is connecting to VFD and few other things. I assume it's a Mesa board but which one? [1]
We all seem to keep running in circles here. Grounding had been mentioned many times, other theories abound, yet the system still shows "occasional sserial error". Occasional error is unlikely happening with good grounding solution unless you have a heavy load that pulls huge current through the ground exactly at that time or a high voltage spike somewhere. In my last post in previous thread I suggested to go back to the beginning and check HW around the data line, both visual and electrical: - cable, connectors including soldered or crimped connections, - metal dust and corrosion on PCB traces, ICs, capacitors, (but I see your box is very clean) I checked one of your pictures and see that you have a PC like power supply mounted on the door. PSU would be better mounted on the main panel, possibly eliminating need for undesirable DC cable extension. How good is the PSU? Are the door and the box grounded to the common ground on the panel? Can't see that in the picture. I see wires at the bottom corners of the analog servo board, one black (left) and three black with yellow shrink tube (right). They are connected to the panel but not together in a star configuration. Where do they go? I don't see one (copper) bus bar for use as a common ground for everything. More close up pictures from different angles would be helpful. Additional questions related to "occasional sserial error" pop up in mind: * what does it mean "occasional"? One error per 100 characters sent, one per 1k, etc.? * what about parity or error correction? * what kind of a command is issued when this happens? * what happens before and after "sserial error" occurs? * what are DC levels on serial connection? * what is the noise level on DC power lines in idle mode and under the load? * does it happen when the door is closed or open? See PSU notes above. * is it always the same sequence of bits/bytes when this happens? * what about mechanical vibration at the time? * is it HW issue at all? What about the software? Are you doing something else on the same system while the CNC code is executing? * Is there firmware in IO interface you need to deal with? * where do you see "sserial error"? Log files or screen popup message? I think it's dmesg but I'm not familiar with this obviously. If log files what else is there before and after? [1] http://www.linuxcnc.org/docs/devel/html/man/man9/sserial.9.html On 01/10/2016 03:44 AM, John Thornton wrote: > Well none of the suggestions about star grounding did any good. In fact > they made the problem worse than before, so bad I could not even get 2.6 > to run. Off this list I was sent the AB servo best wiring practices pdf > which explained how to reduce noise in a servo drive enclosure. I > followed the advise as much as possible and after removing all my ground > wire antennas I was back running with an occasional sserial error. The > short explanation is to terminate the shields to a ground plane as close > as possible to the point where you take the shield/drain wire from the > cable. I still have a cable bundle running to my switch box that is > parallel wires and I might replace that with some twisted pairs. Photos > at 11. > > JT Everybody please trim advertising and other noise at the bottom or other parts that are not relevant in the replies. -- Rafael ------------------------------------------------------------------------------ Site24x7 APM Insight: Get Deep Visibility into Application Performance APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month Monitor end-to-end web transactions and take corrective actions now Troubleshoot faster and improve end-user experience. Signup Now! http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140 _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
