The Craftmans Shop > New from Old
The Sequel - Oh Blimey I bought a CNC Lathe (Beaver TC 20)
PK:
Yeah, it could well be the thing that amp is driving that is causing the problem, I'll test the amp and that transistor tomorrow. At least we have a starting point now...
I kinda suspect there are two faults. One with this negative voltage rail, and another with the probe. I'd expect to be able to see some activity from the IR LED on the probe when it see's the start signal, looking at it with a webcam or phone being just a repeat of your tests..... I'll have a sniff around the photodiode on the TX board tomorrow with a 'scope, just in case the response from the probe is on a wavelength that isn't detected by our cameras. All whilst pondering the best way to get into that probe without screwing up the waterproofing..
PK
awemawson:
PK, if it's like other Renishaw stuff I've opened up, it'll be O ring seals I suspect.
awemawson:
In anticipation of PK working miracles with the Renishaw Probe electronics, I decided that it was time to plan a re-do of it's wiring. As I think I've previously mentioned, it seems to be a field upgrade with the necessary wiring just draped any old place that they could get it. The MI-12 interface unit is hard wired in, and just sitting on a shelf.
I wanted to get the wiring in existing trunking while the lathe cabinet sides are off, and wire the MI-12 interface via plugs and sockets. It needs a 24 volt supply from the main I/O supply in the rear cabinet (2 wire plus screen), an output to the appropriate card in the Siemens 820T controller (again 2 wire plus screen) and a multi-core to the OMM that PK has on the other side of the world (5 wire plus screen)
I chose XLR style connectors as I already had two of the three, arranging that the 3 pole ones were opposite gender to prevent them being able to be confused.
Initially I'd intended to mount them on a bit of the trunking in the cabinet where the MI-12 sits, but then decided that it would actually be easier to mount them in a separate box which then could be fixed to the trunking as an independent item.
So, first let's see the problem
awemawson:
So a quick pencil sketch, rapidly followed by an Autocad drawing whose DWG file was processed by SheetCAM to give me a CNC-Plasma ready file to cut.
I used 2 mm plate, in retrospect I think that this was a bit OTT, and 1.5 mm would have been a better choice as it would have bent more crisply in this small size, but it's come out OK
Having cleaned up the cut profile with a sanding disk, and made sure that the connectors fitted their odd shaped holes, I then bent it up, and soldered the corners. After a bit of a clean up it got a coat of zinc rich paint followed by a coat of satin black.
So it's now all ready to fit - I will probably run new cables rather than disturb the old at this point, as when the OMM returns I don't want the uncertainty of replacement wiring muddying the waters when it comes to testing - anyway the existing stuff is a bit mangled in places (although intact)
awemawson:
Well a bit of progress today. A couple of weeks ago a CPU card for the Sinumerik 820T controller popped up on eBay in the USA at an attractive price - usually people ask silly money for them - whether they sell or not is another matter!
Anyway this one was just about affordable, and it was from a dealer that I'd actually bought parts from before when I was breathing life back into the Traub lathe. Why do you need another CPU card? Well probably I don't and won't, but if I do you can guarantee the only ones will be priced in telephone numbers ! The real reason though was that there is just a faint possibility that the M19 / M20 spindle orientation issue could be CPU based, after all it not only is running the code and handling the interrupts, but also has some of the RAM on board. So as a diagnostic aid, and then ultimately as a shelf spare it was worth it.
So today (having paid the VAT etc on line yesterday) Parcelforce in the shape of Adrian our local man, delivered it. With no more ado I pulled out the original CPU card, put in the new and fired up the machine - ah well no - she's NOT firing up. Oh blast - dead on arrival - never mind - Paypals' 'pay after arrival' has it's uses I thought.
Original CPU card re-installed - oh HECK - shes's not firing up - it's blown something up. :bang:
No, calm down chum, there's RAM on the card, is that part of the battery backed parameter stuff? Sure enough pressing the magic 'Eye' key on the controller when powering up got me into the re-load 'Initial Clear' mode - perhaps it's NOT D.O.A. after all. So new CPU put back in, and again into the 'Initial Clear mode by pressing the Eye key, and I started the long winded rigmarole of reloading all the back up files.
I'd just got to a critical stage when the wife needed urgent help - sheep issues - (there are always sheep issues!) - one with 'fly strike' - one limping - loads of carrying hurdles about, penning up sheep and getting thoroughly filthy - actually it was a nasty fly strike occasioned by a partially torn off horn and consequent blood on a Jacobs lamb and did need urgent treatment.
OK - wash the maggots off my hands and get lunch :bugeye: (ham omelette) then back to the re-loading of the controller. All went OK, all functions work except of course the M19 /M20 spindle orientation. It was a pretty faint hope, but at least the CPU card has been eliminated and now I have a shelf spare.
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version