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Thread: Fanuc OT to DC_CNC conversion.

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    Gold Member Jim Dawson's Avatar
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    Default Fanuc OT to DC_CNC conversion.

    We picked up a Hardinge Conquest 42 CNC lathe. 10 tool turret with live tooling. It has a Fanuc OT controller, about a 1988 vintage.


    Built a rotary phase converter for it, got the machine running and made a few parts. It lacks a lot of capabilities that we would like, has some odd quirks, and the biggest problem is the lack of memory for loading G code programs from modern CAM software. Also we are not able to work on CAD/CAM on the machine computer.

    So the logical answer is to just simply upgrade the computer system to something more modern. So we will be installing a Core i7 computer, a Galil motion controller, a 27 inch monitor, and my CNC software. If one were to buy all of the hardware new, the total cost would be ~$5000 for the upgrade. The good news is that I have the parts on the shelf that I normally paid very little for so the total out-of-pocket will be <$1000


    The machine is a 3 axis, X, Z, and Spindle, plus the live tooling drive and the 10 position tool turret. So that means a total of 5 axes to control. I was surprised to find the the turret is also servo controlled, I thought it was hydraulic rotated. The hydraulics only operates the locking mechanism.

    With minimal documentation this is going to be a bit of a challenge, but doable. The first order of business is to identify all of the I/O points that are needed to run the machine and create an I/O map to be able to determine the requirements of the I/O.

    We expect that we'll be making chips again by mid next week. (These pictures were taken on a Tuesday)

    So here are the before pictures.

    Computer


    Cable connector block


    A little wider view


    Existing operator panel


    The main electrical cabinet



    And the I/O blocks on the door



    So the challenge is to figure out what each I/O point is connected to and decide what is actually needed and what needs to connect back to the new computer. Most of the controlled devices (contactors, valves, etc.) are 100VAC (yes, 100VAC) and are switched by the relays. The other board is the inputs from limit switches and sensors that are 24VDC. For the most part I'm going to be probing wires to trace them. The documentation that I have is not complete.

    The interconnect terminal unit has been removed. A lot of cables hanging out there, and most of them are not needed. I sometimes think that manufactures add additional hardware just to make it look complicated. In reality, there are only about 50 or 60 connections total that have to be made, it just doesn't require a couple dozen 50 and 25 conductor cables.


    Continued in next post............


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    Fanuc OT to DC_CNC conversion.-img_1880-jpg   Fanuc OT to DC_CNC conversion.-img_1759-jpg   Fanuc OT to DC_CNC conversion.-img_1896-jpg   Fanuc OT to DC_CNC conversion.-img_1907-jpg  

    Last edited by Jim Dawson; 02-09-2018 at 05:49 PM.
    Jim Dawson
    Sandy, Oregon, USA


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    Gold Member Jim Dawson's Avatar
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    Default Re: Fanuc OT to DC_CNC conversion.

    Continued from post above......

    Operator panel, and computer removed




    An empty computer cabinet. New board mounting plate installed on the door. Needed parts ordered today, they should be here Friday if everything goes well.





    Had to do a little surgery on the new computer case, was just a bit big to fit the way we wanted.





    And the new computer. Only took about 6 hours to update Windows, and load the software. Not shown in this picture are the 2 installed Galil cards. Galil cards, plural because I only had 4 and 1 axis cards on hand, so to drive 5 axes, I need to install 2 Galil cards. I've done this before so I know it works. I only need coordinated motion for 3 axes, so I can get away with an orphan card.





    Still have a few cables hanging out of the electrical cabinet, I'll remove the unneeded ones when I get it all figured out.



    As it turns out, it seems that the motor encoders do not connect to the servo drives, they went straight to the computer. This is a good thing, that means they will connect directly to the Galil card which is my prefered method. What I can't exactly figure out is how the servos are commutated without any feedback, must be using some type of sensorless vector control. The input the Fanuc drives is just a normal +/- 10V analog command signal. I hope the spindle servo drive plays nice, it has an ''orient'' feature driven from a separate spindle encoder, I'm hoping I can figure out how to disable that or at least get the drive to ignore it.

    Some of the parts came in today, and I should get the rest tomorrow (Friday). So I expect by Monday we'll have the wheels turning, and after a little software debug we'll be making chips by Wednesday.


    The new software is coming along, I'll post a screenshot in a few days.


    More later........
    .

    Attached Thumbnails Attached Thumbnails Fanuc OT to DC_CNC conversion.-img_1911-jpg   Fanuc OT to DC_CNC conversion.-img_1912-jpg   Fanuc OT to DC_CNC conversion.-img_1914-jpg   Fanuc OT to DC_CNC conversion.-img_1915-jpg  

    Fanuc OT to DC_CNC conversion.-img_1909-jpg  
    Jim Dawson
    Sandy, Oregon, USA


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    Gold Member Jim Dawson's Avatar
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    Default Re: Fanuc OT to DC_CNC conversion.

    A little update.

    Got a little more work done, got the I/O blocks and I/O rack mounted on the computer cabinet door, and some of the cables run and wired in.



    And wired in. Still have a whole pile of cables to connect.



    I did hit a bit of a stumbling block, I was able to easily generate a map for the outputs just by turning things on, things like valves, brakes, etc., but I have no correct documentation for the inputs, limit switches, sensors, etc. So I have to trace down every required input back to the device to generate the input map.

    Attached Thumbnails Attached Thumbnails Fanuc OT to DC_CNC conversion.-img_1918-jpg   Fanuc OT to DC_CNC conversion.-img_1920-jpg  
    Jim Dawson
    Sandy, Oregon, USA


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    Default Re: Fanuc OT to DC_CNC conversion.

    Some fanuc drives get a synthesized tach signal from the control. On the linuxcnc side people have created a tach signal from the encoder velocity - then ran that into the fanuc drive.

    sam



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    Gold Member Jim Dawson's Avatar
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    Default Re: Fanuc OT to DC_CNC conversion.

    Great information ! Thank you Sam.

    As near as I can tell so far, there is no encoder feedback of any kind connected to the 3 axis drive. But I have not completely mapped the CN1x connectors. But so far it seems that the only I/O used on the CN1x connectors is Enable, Analog command, and Fault output. If there is some kind of feedback signal to that drive, it has to come through the CN1x connectors, there are no other signal connectors on that drive.

    If this gives me too much trouble, I'll rip out the Fanuc drives and replace them with more modern drives that actually have available documentation.

    Jim Dawson
    Sandy, Oregon, USA


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    Gold Member Jim Dawson's Avatar
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    Default Re: Fanuc OT to DC_CNC conversion.

    Quote Originally Posted by samco View Post
    Some fanuc drives get a synthesized tach signal from the control. On the linuxcnc side people have created a tach signal from the encoder velocity - then ran that into the fanuc drive.

    sam
    Sam you are absolutely correct. Your post and a conversation with Al_The_Man convinced me that we were going down the wrong path.

    So after much research we have decided to rip out all of the Fanuc axis servo hardware and install DMM servo motors and drives. We will be installing 1.8 KW servos on all axes. For the most part they bolt right in, no adaptors needed. I do have to make an adapter plate for the Z axis drive. The X axis, turret, and live tool drive have standard 130mm mounts.

    I originally thought the Fanuc 7.5 KW spindle motor was a PM servo motor, but it turns out it is a standard(ish) 3 phase motor so we are going run it with a GS3 VFD from Automation Direct. We'll see how well I can make it position, with the Fanuc system it was spec'd as good for 1 degree. With modern hardware I'll bet I can do much better than that.......We'll see how well that works out. If I'm not able to get it to position the way I want it to, then I will install another 1.8 KW DMM servo for positioning in addition to the 7.5 KW spindle motor. I can just clutch it in and out as needed.

    Going to have a lot of Fanuc hardware for sale soon if anyone needs it.

    Stay tuned for more.........

    Jim Dawson
    Sandy, Oregon, USA


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    Gold Member Jim Dawson's Avatar
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    Default Re: Fanuc OT to DC_CNC conversion.

    I haven't updated this for awhile. Am making progress.

    The new servos and the rest of the hardware came in last week.



    The DMM Dyn4 servo drives


    Got the servo and control relay panel wired up and installed in the cabinet, 4 servo drives, contactors, e-stop, and control power relays all fit in about the same footprint as one of the original drives. Electronics keep getting smaller.




    Making progress.

    Attached Thumbnails Attached Thumbnails Fanuc OT to DC_CNC conversion.-img_1952-jpg   Fanuc OT to DC_CNC conversion.-img_1954-jpg   Fanuc OT to DC_CNC conversion.-img_1961-jpg  
    Jim Dawson
    Sandy, Oregon, USA


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    Gold Member Jim Dawson's Avatar
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    Default Re: Fanuc OT to DC_CNC conversion.

    Been working on the lathe in my spare time and am making progress. Proved out all of the I/O, power, and hydraulic functions and corrected the few wiring errors. Fired up the spindle for the first time today and bench tuned the new servos yesterday. Everything plays nicely with the computer. So far so good. Should have the servos back on the machine tomorrow then I can run the axes and finish final servo tuning. Then I get to debug the software.

    Jim Dawson
    Sandy, Oregon, USA


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    Gold Member Jim Dawson's Avatar
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    Default Re: Fanuc OT to DC_CNC conversion.

    I have all of the servos installed and most of the covers back on. Tuned the servos today and also figured out that I have a small logic problem in the X brake electrical logic. Turns out that hitting the E-stop doesn't de-energize the brake, and the X-axis drifts down. Need to do a bit of rewiring to pull the brake power after the E-stop relay. Also figured out that I need a travel limit override, prying the axis off of a limit with a 2x4 sucks, I'll fix that in the morning.

    Here is the Z axis motor mount adapter that my son cranked out for me. This was the only axis that needed an adapter, the rest were bolt in.

    Fanuc OT to DC_CNC conversion.-img_2005-jpg

    and the motor mounted

    Fanuc OT to DC_CNC conversion.-img_2007-jpg

    And the stereo system (above the monitor) Works pretty good. The box between the speakers is where the front panel USB ports will be. On the screen is my mill software, it will change a bit in the next few days to be lathe specific.

    Fanuc OT to DC_CNC conversion.-img_2009-jpg

    And finally a video of the turret going round & round. Not doing much but running the motor, but at least it runs.



    Tomorrow I'll make some needed wiring changes and figure out why I don't have computer control over the spindle. Probably just a setting. When that's done I'll start working on the software. Hopefully by Monday we can make some chips.

    Attached Thumbnails Attached Thumbnails Fanuc OT to DC_CNC conversion.-img_2005-jpg   Fanuc OT to DC_CNC conversion.-img_2007-jpg   Fanuc OT to DC_CNC conversion.-img_2009-jpg  
    Jim Dawson
    Sandy, Oregon, USA


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Fanuc OT to DC_CNC conversion.

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