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Thanks for the response, sorry for the late reply.

That configuration sounds good but after using the config tool linked above I am slightly favoring the 7i77 + 7i96S for the additional IO/less cards/similar price. Is there any reason that's a bad idea?

another question I have after reviewing the 7i96S Documentation is about the analogue spindle interface. my spindle controller is expecting to see a voltage between 0-10v for the speed reference, the 96s Docs say "The voltage supplied between SPINDLE+ and SPINDLE- must be between 5 VDC an 20 VDC" this is referring to the voltage between spindle- and spindle+ ( ie 0 to 10 is a change of 10 and so fine) NOT the voltages that spindle- and + must fall between (ie spindle- being 6 and + being 15) right? In other words 0-10v for spindle-+ should be no problem right?

Thanks

Exactly. I've printed it already..

That's a huge step for me, thanks for your patience.

So I guess, that I need to go back to mesact, call up the 7i77 again, enter as much machine info as I can for all axes and the spindle, and from then on I am away from that GUI and into text.

LinuxCNC can do up to 9 axis, so yes you can do a single axis CNC (which is what an ELS is). I did that on my Boley, for which I had no change gears. I just made up a bracket to mount a motor and pulleys to drive the lead screw, kludged up an encoder, and PSU, and used a PC to control it. Was never a permanent solution, I only used it to cut the nose spindle thread in a backing plate.

Backlash is less of an issue for a lathe than a mill, as you mostly don't change direction with the tool in the part (at least not on both axis), and you don't have the issue of climb milling. My mini lathe has pretty bad backlash on both axis, but can still turn somewhat precise parts open loop using LinuxCNC's backlash compensation.  I suspect that closed loop with linear encoders, with significant backlash in the screws, would be pretty tricky to tune the PID loops on.
However, as Cornholio said, it is best to simply engineer out the backlash. The Schaublin has no linear encoders, so I am DROing off the motor encoders. I would not buy a ballscrew kit with cheap rolled screws. Get some nice C3 or better ground ballscrews pulled from a fab in Korea, and make up you own mounts.

One of the big advantages of CNC is that you can put on enclosure, or at least better shielding around the chuck and constrain the mess.
You mentioned using an ELS to cut to a shoulder. Nicer is using two axis CNC, to cut to the shoulder, then retract out before it starts rubbing and chattering, and returning for multiple passes
However I also really like manual lathes for quick bodge jobs which need no precision, and like the "feel" of machining on a manual lathe.

As Cornholio has said, if you are going to end up with a full CNC, you are probably better off doing it all in one go. Doing a mixed CNC/manual interface is harder to do well, than one or the other.
With the Schaublin, I found my initial use of the machine, with a loose wireless keyboard, and touch monitor leaning aginst the tailstock, to be pretty sketchy and unsafe.  I felt a lot more comfortable with the safety once I built the control module with some physical buttons like feed hold, the encoder for feedoverride, and the jogging joystick etc.

The 7i73 is so cheap, having a single Cat 5 cable to you human interface can saves hour of discrete wiring.

I choose that set of diverse cards on the Schaublin for two reasons:
1/ when I went through and made a list of all the I/O, encoders, etc it would need, it was not going to work on one of the integrated cards. I currently have six encoders, (Spindle, X motor, Z motor, feed override, spindle override, jog override), with two more planned ( X Jog wheel, and Z jog wheel on a manual jog pendant). I also need a second 7i84, instead of the sketchy relay board to use available 7i84 5V outputs to switch 24V loads.
2/ I knew I would have a space challenge, and breaking up the cards reduced the need for a single big footprint in the control cabinet.

On the mini lathe, I just used a 7i96, and on the Maho a 5i25/7i77 (The 7i97 didn't exist yet), plus a 7i84 as it needed addition I/O.
Cheers,
Mark
 

Thanks for all the help - I'm 1 failed encoder away from being able to use MDI to test the spindle. I may try that simple HAL file if I get time.

Also  I'm not sure if pncconf's open loop test can really access much other than
the axis analog outputs. A better test might be a very minimal hal file:

loadrt hostmot2
loadrt hm2_eth board_ip=10.10.10.10
loadrt threads
addf hm2_7i92.0.read thread1
addf hm2_7i92.0.write thread1
start
loadusr halshow

And then run this file with:

halcmd -f testfile.hal

or just

halcmd -kf

 and enter the lines by hand or copy-paste

At this point you should be able to set and view pins
with halshow

When done you will need to run:

halrun -U

To unload the drivers.




 

Maybe this helps
forum.linuxcnc.org/10-advanced-configura...ning-detailed-how-to

Right now I can't get to MDI as the encoders are giving me fits, I can only move in "Open Loop" test mode in PNCConf. Once I get my encoders sorted, I'll try this, but right now I have zero response in PNCConf.

I would set the spindle speed to 1/2 full scale (3000)

(MDI)
M3S3000

and see if these make sense

hm2_7i92.0.7i77.0.1.analogout5
hm2_7i92.0.7i77.0.1.spinena

Then check the analog 5 output

So I'm in PNCConf and I have my linear motors moving in open loop test mode, but when I go to open loop test mode on the Spindle tab, I get no DC Voltage output on the 7i77 Analog output 5.  HAL shows an output, but the multimeter shows nothing.  Attached are my 2 hal files and my ini.  Also is there a way to have a different max linear speed for my Z axis?  The head is heavy and the motor is tired, doesn't want to move it at 300ipm, but the x and y have no problem.

I'm another with a KMB-I. Mine is 1981 B control, and is fully functional as is. Pretty much original. Parajust VFD, ServoMate ±12V signal Servo boards and has the same Electro-craft 90volt brushed motors with built in tachos and Litton 200 cpr quadrature encoders almost as described here. forum.linuxcnc.org/12-milling/39662-hurc...s-cnc-update?start=0  It has the Bristol Erickson quick change #30 spindle. Oh yes, I do also have Buddy Maughon's tape emulator. It had stood unused in a private workshop from 2001 to 2021. Had to replace a variety of electronic pieces in the control and parajust to get it to start and run, six month entertainment, prodding with a scope and voltmeter, but worth is as only run for 1938 hours, so straight and true. Oiler, spindle, brake safety pressure switch coolant systems, flood and mist etc all in good order.

My requirement is 'only' that I want to be able to send it some G-code so I can machine some weird 3D shapes.
So, I'd like to be able to swap to a Linuxcnc front end, but in a way I could perhaps swap back to the conversational system I have come to admire and like. I guess in one dream, maybe a Hurco conversational front end could be built for linuxcnc...
Yes, I know the obvious solution would be a B to BX controller upgrade. Would I think do all I need, but the current price is so much more than what I paid for the whole machine, I'm having a hard time justifying that kind of expenditure.

So, I've a running linuxcnc 2.9.2 app as well as mesact installed on a Raspberry PI-5 and a 7i95T ethernet on order from JT, too many axes I know, I am also aware the the three shaft encoders will need more pulses, and can handle that as have already fitted one USdigital item to deal with the Y encoder that had a chip out of the glass scale and several lines missing. The USD part needed a mounting base making, but otherwise worked straight out of the box. 
But then I kind of missed the point with all the daughter board options, and I would appreciate some clear sighted and informed opinions on which ones I really need to make this dream a possibility. 7i77 or 7i83 for instance might be ok for the servos, but then they've 10V versus 12V output that the ServoMate is expecting. Secondly I probably also need maybe a 7i73 to interface with any jog generator and buttons on the panel.

Apologies for writing so much, but I'm hoping that the detail will be helpful to someone some day.

Fingers crossed.

Ok so i tried the following:
-swapping the two DB25 cables
   => sadly no change in behavior (since this would have been so easy to fix)
-changing my C-Axis from encoder 03 to 04 and Spindle from 05 to 03
   => C-Axis now turning endless during homing routine
   => Spindle Index actually visible in halscope on highest sample rate when turning by hand


I also tried (but failed) to rewrite my hal to change between the two DB25 ports on the 5i25 to pin the cause to the 7i77.
Then I created a test machine with PNCCONF to get the 7i77 connected through the internal DB25 port of the 5i25 (P2), but I couldn’t get it to work. After some googeling I now think this is embedded in the firmware of the 5i25, if that is so, is there a firmware where the ports are swapped (7i77 + 7i74)?
See readhmi attachment for current configuration.

What are my options if the 7i77 is damaged. I have a 7i73 laying around waiting to be mounted into a pendant. Can it be used to connect the spindle encoder? Or is there a similar card to the 7i77 without the I/O pins to use for all the encoders and analog signals for the drives?

Hello,
Today I ran into a problem trying to connect my spindle encoder via a Mesa 7i77.
The Pin encoder.05.input-index is always shown as high, even when I hardwire that input to ground. See the Picture of the Halscope.
The Index Signal is OK, I confirmed it with my Oszi. I have also tried quadrature mode and single ended mode on both +I and -I inputs, always with the same result.

Could it be that the Mesa card input is somehow fried? This was my first thought but on the currently free encoder 04 it gives the same behavior, but maybe this one is also toast. I did not test any other encoder channels, as there are the four axis connected. No issues there at all.

How is the encoder input-index connected in software? I looked at the HAL pins to see if maybe something else is overwriting that signal, but this isn’t even connected to a net, as far as I could see.

Would it be possible to use a different input (not an encoder input) as the Z-signal, as it is named in the Encoder documentation?

I did an SM-1 (the knee mill cousin of the KMB-1) with a 5i25/7i77 combo and reused all servos and drives. I think the only electronics I added were the computer with 5i25/7i77 and a VFD for the spindle. I did away with the vari-speed mechanism in favor of VFD control.

klopp wrote:

The 7i96S doesn't have a dedicated floating enable output, that's why you need a 7i77 which has that. I'm not super deep into that topic, does it make sense to change it so any output counts as enable?

Pretty sure 7i96S has two (or more) high current outputs and pretty sure they are all fully isolated.
I might be wrong though.
And, yes, i would see any output as enable output.
The only stuff that might require isolated outputs are spindle VFD and Plasma, not always. So 7i96S is good for both.
Again, thank you, this should help a lot.

Just did a quick test and found some bugs:
-7i96S is always named 7i76S, should be 7i96S
-see attached, 6 inputs 4 outputs 1 enable 4 stepgens 1 encoder and 1 spindle comes back with 7i76S (should be 7i96S) and 7i77 and all combos using 2 cards, while everything should be only a 7i96S
Nice idea and implementation, though, thank you. And showing connection between cards is also very nice.
Great job!