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IndustryArena Forum > MetalWorking Machines > EMCO CNC Machines > EMCO Lathe > Retrofitting a Emcoturn 120p, keep the original spindle encoder?
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  1. #1
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    Jul 2016
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    Retrofitting a Emcoturn 120p, keep the original spindle encoder?

    Hi!

    As topic say, i'm doing a retrofit on an Emcoturn 120P (new ac spindle motor, new open-loop vfd, new closed-loop steppers, linuxCnc etc.)

    but i have a question i can't figure out by reading the other retrofitting threads, the encoder for the spindle, most people removes the original and put's a aftermarket on, is there any special reason for this?

    do they easily break? or is it problematic to get linuxcnc to receive the signals from the original encoder?

    if i would to switch it for another one, what should i get? i have seen some people go for the CUI INC AMT102.

    Best regards Victor

  2. #2
    Join Date
    Jan 2005
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    15362

    Re: Retrofitting a Emcoturn 120p, keep the original spindle encoder?

    Quote Originally Posted by Granathe View Post
    Hi!

    As topic say, i'm doing a retrofit on an Emcoturn 120P (new ac spindle motor, new open-loop vfd, new closed-loop steppers, linuxCnc etc.)

    but i have a question i can't figure out by reading the other retrofitting threads, the encoder for the spindle, most people removes the original and put's a aftermarket on, is there any special reason for this?

    do they easily break? or is it problematic to get linuxcnc to receive the signals from the original encoder?
    The encoders don't break, they just have a resolution that does not suit what some control can accept, in most cases, they work fine, if your control can use them, Linux with the right Breakout Board should be able to use the original Encoder

    What happened to your original spindle drive motor, they are normally used for any retrofit
    Mactec54

  3. #3
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    19

    Re: Retrofitting a Emcoturn 120p, keep the original spindle encoder?

    Quote Originally Posted by mactec54 View Post
    The encoders don't break, they just have a resolution that does not suit what some control can accept, in most cases, they work fine, if your control can use them, Linux with the right Breakout Board should be able to use the original Encoder

    What happened to your original spindle drive motor, they are normally used for any retrofit
    Ok, Linuxcnc with Mesa card looks like it would handle 2048 ppr so i should be ok then? if max pulses is the problem i should be able to switch to a disc with 1 or 4 slots?

    the spindle motor itself is ok from what i know but the TM02 system won't fire up, and getting a 3kw 400v dc drive is far from cheap, at least in Sweden.
    i was looking at reusing the cards in the TM02 controller that runs the spindle but some have repairs (added cable between soldering joints etc.) and i don't know if they have been successful.

    Edit: according to the wiki the encoder has one pin: number 3 / green that does 1ppr, why don't people use this if the pulse resolution is to high?

    Br Victor

  4. #4
    Join Date
    Jan 2005
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    15362

    Re: Retrofitting a Emcoturn 120p, keep the original spindle encoder?

    Quote Originally Posted by Granathe View Post
    Ok, Linuxcnc with Mesa card looks like it would handle 2048 ppr so i should be ok then? if max pulses is the problem i should be able to switch to a disc with 1 or 4 slots?

    the spindle motor itself is ok from what i know but the TM02 system won't fire up, and getting a 3kw 400v dc drive is far from cheap, at least in Sweden.
    i was looking at reusing the cards in the TM02 controller that runs the spindle but some have repairs (added cable between soldering joints etc.) and i don't know if they have been successful.

    Edit: according to the wiki the encoder has one pin: number 3 / green that does 1ppr, why don't people use this if the pulse resolution is to high?

    Br Victor
    I guess they did not find that it had the single ppr. ( called Z Index pulse or Index pulse )

    That makes sense, with the spindle motor, my 120 PC has a 3ph Ac motor on it, the 140T I have has the 400v DC spindle motor 5.5Kw
    Mactec54

  5. #5
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    Jul 2016
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    19

    Re: Retrofitting a Emcoturn 120p, keep the original spindle encoder?

    Quote Originally Posted by mactec54 View Post
    I guess they did not find that it had the single ppr. ( called Z pulse )

    That makes sense, with the spindle motor, my 120 PC has a 3ph Ac motor on it, the 140T I have has the 400v DC spindle motor 5.5Kw
    Ok good news then i will keep the encoder!

    Yeah if you have an Ac motor it is much easier lucky you!

    Thanks for your help.

    Br Victor

  6. #6

    Re: Retrofitting a Emcoturn 120p, keep the original spindle encoder?

    You can thread with the single index pulse. Linuxcnc supports rigid tapping with a quadrature encoder on the spindle, so many choose to replace the original to take advantage of this.

  7. #7
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    19

    Re: Retrofitting a Emcoturn 120p, keep the original spindle encoder?

    Quote Originally Posted by Diesel_Pilot View Post
    You can thread with the single index pulse. Linuxcnc supports rigid tapping with a quadrature encoder on the spindle, so many choose to replace the original to take advantage of this.
    Ok thank you for explaining, i read something about quadrature but did not get what it was about, i will start with the original encoder and if i feel i could use the quadrature functionality i will replace it later on.

    Br Victor

  8. #8
    Join Date
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    15362

    Re: Retrofitting a Emcoturn 120p, keep the original spindle encoder?

    Quote Originally Posted by Diesel_Pilot View Post
    You can thread with the single index pulse. Linuxcnc supports rigid tapping with a quadrature encoder on the spindle, so many choose to replace the original to take advantage of this.
    An Encoder that uses quadrature is an incremental Encoder

    It does not matter if it is Incremental or Absolute, the Index Z Pulse, does not change it is 1 Pulse Per Rev on both types of encoders, so this has noting to do with whether the encoder is quadrature ( Incremental ) or Absolute, for a single Index Z pulse stays the same on both types of Encoder
    Mactec54

  9. #9

    Re: Retrofitting a Emcoturn 120p, keep the original spindle encoder?

    Obviously, the index signal is the same. The reason people use a quad encoder is not for the index signal, but for increased position resolution and direction output. In the video below you can see the result. In this case the chuck is turned by hand. The lathe is programmed, but spindle is not on. Z waits for index, then uses quadrature signal to sync Z to spindle. You can't do this with a single pulse per rev. The end result allows rigid tapping and more accurate threading. There is a video of this with the chuck being turned both ways and the Z axis following along forward and backward in the middle of the thread, but I couldn't find it.

    https://www.youtube.com/watch?v=AW5-A_ru3-I

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