Hi Gene! Anno domini 2019 Fri, 24 May 08:56:41 -0400 Gene Heskett scripsit: > On Friday 24 May 2019 04:48:50 am Dr. Nikolaus Klepp wrote: > > > Hi Gene! > > > > (This is not directly a TDE question, so it might be of no interest to > > a lot of readers, but anyway ...) > > > > If I recall correctly, you have mentioned somewhere that you have a > > RPi + TDE + 7i90HD running. Yesterday a 7i960HD ended up on my desk. > > Now I want to build a new CNC with RPi + TDE + 7i90HD, but I am stuck > > at how to flash the correct firmware to the card. I understand that I > > need mesaflash to flash 7i90_spi_svst4_8.bit > > (http://linuxcnc.org/docs/devel/html/man/man9/hm2_rpspi.9.html) from a > > pc via what? Centronics cable? Do you have a link to the needed > > cables? And maybe a working linuxcnc configuration? > > > > Nik > > i bought a roll of 26 wire cable and a bunch of connectors 26 on one end > and db25 on the other, and then discovered /I had to peel one wire off > the far edge of the cable. So it fits the parport on the pc, and the 26 > pin socket on the 7i90. I'd had some cable failures since, 2 or so, > mainly from inadequate smunch when assembling the cables. I have never > used the terminator board for a mesaflash session, but you'll need one > at the pi header. Get it from OSHPark, Jon at Pico systems can give you > the oshpark part number. 3 of those is less than a tenner. You'll need 3 > little grain of sand surface mount 120 ohm resistors per board, a 40 > pin shrouded male connector that fits the pis header on one side of it > and a 26 pin shrouded male socket on the other side. The termination is > simple, src term but does allow slightly longer cables, but I mounted a > fan from a video card under the pi and mounted it upside down so the > heat sinks are right over the fan. Turning the pi upside down put the > pi's gpio hearder on the lower edge, which allowed me to use a cable > about an inch long. > > Now, the 7i90 is a 3 volt card, and ANY noise will blow things. So get 3 > 7i42TA's, a 6 pack of 50 pin scsi connectors to fit the sockets on the > 7i90HD, and a hunk of old 50 wire scsi cable you can cut up to hook the > 7i42TA's to the 7i90. The 7i42TA's contain the noise absorbers that > protect the 7i90HD, allowing the 7i90HD to work in 5 volt circuits, and > they give you rows of the green screw terminals to greatly simplify > hooking all this up. I made a stack useing most of a standoff kit and > stairstepped them on top of the 7i90HD, so none of my 50 wire cables are > over 5" long. > > I've got a hal file from hell, lots of gingerbread and have made a much > slower thread than 1 khz servo-thread, something in the 100 to 200 hz > range is working well and I put all the hand controller stuff in that > thread, else the servo-thread would be too long to make 1khz work. TDE I > always figured needed more iron than a pi had to spare, so mine is still > running the default raspian xfce4 for a gui. With only a gig of dram, > my thinking was that the pi would get bogged down in swap. Video refresh > in real time is but a dream, 5-7 frames at best using xfce4. You do > eventually get used to it. > > You'll need to locate a 3.4-9-rtai-686-pae=3.4.0 kernel and mark it with > a *hold to keep apt from replacing it. It has one major bug, so the > first thing you do after bootup is find the keyboard/mouse setting > uttility in the menu, and make a change so it will be saved so that key > repeat is limited to 15 cps or so. It boots up at about 1500 cps and > that floods the usb port nearly everything but the spi and wifi goes > thru to get to the outside world. Put bluntly, that causes the pi to > lose key-up events, leaving the machinery you just jogged, jogging until > you hit the key quickly, sending a keyup before the repeat kicks in or > it hits something. Thats broken quite a few carbide tools by running > then into the workpiece when the spindle isn't turning. There are a > couple later kernels, but they all have this same bug. They may work now > that we know how to fix it. Until the after boot thing is done, use very > quick pecks on the keys. > > How big is the lathe? And how will you drive the spindle? I toured the > local recycle places and found a pair of 1hp 3 phases on a 50 year old > air compressor that came in from the local horsepistol during a remodel, > and a 50 dollar bill got the hoses unfurled to cut them off the pads. I > ordered bearings and replaced them in one motor, saveing it as a spare, > and put the other on the end of the cables from a 1.5 horse rated vfd, > and have a 30 amp corfam brick wall filter near the vfd output and > another at the vfd's input, and radiated noise has not been a problem. I > used a mesa spinx1 to translate the pwm to analog controls for the vfd. > I can run this motor at 10hz with this vfd for around an hour before I > need to let it cool. Obviously I set a current limit in the vfd to not > exceed the motors FLA, and its all Just Worked. > > Having spare i/o's, so I also have a pair of 40 amp SSR's rigged to turn > off all motor power when motion is disabled by the F2 key. So I can > leave power on the pi full time. I also have a pair of the MPJA dials > mounted on a replacement apron, and thats more gingerbread x2 in the hal > file, but that gives me a 5 speed jog that works just like the hand > cranks used to for manual control. Down to .0002" per click. > > My compound was smashed by a fallover sometime in its pre-gene history, > so its a solid block of cast iron carved from a free sprue from the > foundry that makes wheels for whites large cars (they are here in town) > now (linuxcnc _is_ the compound as it can drive both to get any angle > you need to a higher accuracy than you could ever set a compound to, so > neither of my lathes have a compound today.) > > The same fallover that broke the compound, came to a sudden stop hard > enough that the weight of a mounted chuck bent the spindle just a tad > so I had to regrind the MT5 in it by about 5 thou, and regrind the > backplates to get the chucks running true again. And I've put screw comp > in the hal to compensate for most of the bed wear, diddling X by up to 3 > thou depending on Z position. So I can turn a pretty good cylinder now. > I've also made clamps to prevent unscrewing a chuck with the belt > yelping turnaround's that rigid tapping demands. Turning around a 40 lb > chuck at 250 revs takes quite some power. :) I've got some hal to tell > me how far it travels AFTER the reversal command has been given, and I > shorten the tap depth in the G33.1 accordingly. > > I hope some of this saves you some time and headaches in running > machinery with a pi. > > *hold, here is the contents of my /etc/apt/preferences.d/kernel.pref > file: > ================================ > Package:linux-kernel > pin: version 4.4.4-rt9-v7+ > Pin-Priority: 1001 > > Package: linux-headers > Pin: version 4.4.4-rt9-v7+ > Pin-Priority: 1001 > > Package: raspberrypi-bootloader > Pin: version 1.20170427-1 > Pin-Priority: 1001 > > Package: raspberrypi-kernel > Pin: version 1.20170427-1 > Pin-Priority: 1001 > ================================= > > Good luck Nik. > > Cheers, Gene Heskett How did you get the firmware onto the 7i90? Is there a commandline switch for the mesaflas-program to tell it to use the correct /dev/tty? BTW, this nice device will only drive only a lot of RC servos dor an adaptive mirror assembly, so I'm quite sure it will work as intended. Next thing for CNC will be a 7i76e :) Nik -- Please do not email me anything that you are not comfortable also sharing with the NSA, CIA ...