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The ghost in the machine.
If a tree falls in the forest and no one's there, does it make a noise?
No, because by definition if the sound waves don't reach any ears it wasn't a sound
The ghost in the machine.
If a tree falls in the forest and no one's there, does it make a noise?
That's only one definition. There are others.But that’s it, it’s a vibration not a sound, it only becomes a sound when our brains turn the vibrations from our ears into a sound. vibrations can be in many frequencies most of which we are unable to detect so are those silent ?
Yes but it’s a family friendly forum and we cannot discuss those sort of vibrations on hereThat's only one definition. There are others.
I've been chasing an intermittent fault on my home brew CNC Plasma Table for ages, and I THINK I may have bottomed it at last. Symptoms were that after maybe half an hour of use or maybe much longer I would loose control of the steppers. Mach3 screen positions would change but not the steppers.
Now as it's electronics are in an industrial cabinet with a safety interlock it was impossible just to 'open the box' and measure stuff. Fault most often arose at the end of a job, and then the other day I noticed that a sharp tap on the cabinet would bring on the issue. OK overcoming the interlock I started running with the door open and applied the 'tap test' ie tapping in the manner of a reasonable man with an insulated screwdriver handle. I soon narrowed it down to the area of the Omron relay that is my Estop.. Could be wiring, the relay socket or possibly the relay itself.
View attachment 447818
Wiring seemed sound as a bell, socket looked fine as did the relay. Spare relay and socket ordered, which arrived today. Quick test to prove that I could still bring on the fault (I could) then install the new relay. Much tapping banging and thumping later - fault gone.
That was 6 hours ago, and I can no longer induce the fault
The offending relay:
View attachment 447819
My theory is that as the coil is powered all the time it must run a bit warm and the way it is mounted it is under the four sets of change over contacts - spring retainer not quite strong enough and vibration (or me thumping it!) was inducing contact bounce tripping the 68 volt power supply for the stepper motors.
. . .trouble is with intermittent faults . . how long before you KNOW it's cured !
Exactly that, the hard hats..I went on a course with a couple of lads from work "logical approach to fault finding", when the tutor found out which company we worked for he said "you'll never get a chance to apply what you've learnt", he was right, by the time we were a couple of minutes into a breakdown there would be managers/supervisors shouting "change this, swap that" instead of taking the logical approach
If a man speaks in a forest, and no woman hears him, is he still wrong ?No, because by definition if the sound waves don't reach any ears it wasn't a sound
If a man speaks in a forest, and no woman hears him, is he still wrong ?
Thanks Pete, yes so far all seems well. Yesterday I left it powered up for a good 12 hours with no issuue, and today I cut a 'Tree off Life' which is a complex path set and a lengthy cut both in terms of time and cut length, with no problems. Quite a relief as unreliable kit is a pain.I think you can call it done. Well done finding the fault, even with all the clever test equipment sometimes the frying-pan test is all you need. Intermittent faults are the bane of our life on the demo robots I've sent the same machine back 3 times because it would power up fine in the workshop but knock the earth leakage trip out on site. Workshop blamed the site power, site blamed the machine. The thing is, we had three other machines on site all running fine so the last time I sent it back I told them if they sent it again I wouldn't even try to unload it.
I know a guy who bought an industrial waterjet, it packed up one bank holiday weekend when he had a big job to complete. It was down the whole weekend until the seller came back from his golfing holiday, and he just said "bang the cabinet door, sometimes the interlock switch sticks". One bang on the door and it sprang into life
Sound is a vibration that propagates through air, typically. Whether or not it's heard is irrelevant.
Interestingly Big Clive did a video some time ago about fake Omron relays over heating. Now mine probably is a fake as it was only £4.50 on ebay - genuine ones (presumeably) on RS components are about £15 so if I have further issues I'll get a real one!it manifests as a smell
what thickness is that?Thanks Pete, yes so far all seems well. Yesterday I left it powered up for a good 12 hours with no issuue, and today I cut a 'Tree off Life' which is a complex path set and a lengthy cut both in terms of time and cut length, with no problems. Quite a relief as unreliable kit is a pain.
View attachment 448052
6 mm - well actually probably 6.35 as it's old imperial stock.what thickness is that?
nice, looks like it cuts that no problem!6 mm - well actually probably 6.35 as it's old imperial stock.