Nachi 8608 Retrofit

Discussion in 'Electronics Resources' started by shredability, Oct 31, 2013.

  1. shredability

    Thread Starter Member

    Apr 1, 2012
    This is a bit of a interesting project I've been working on. We have come into possession of a Nachi 8608 six axis robotic arm. (picture below)


    The robot was built in 1988, so as you imagine the controls are a bit old, they came in a huge cabinet with four layers of circuit boards, ruffly 4' x 2' stuffed with DIP logic, EPROM, Motorola uC etc...

    We figure switching out the controls is a must, but we would like to save the motors, encoders and possibly the drives. Unfortunately there is zero documentation on any of these things. Even the nameplate data has been rubbed off on most of the parts.


    On these drives we have all the power connections on the left side, from top to bottom:

    -Input power (100VAC)

    -Motor connection, does anyone know what this picture means? I've never seen anything like it. My best guess is center tapped DC or AC w/ earth ground.

    -Earth Ground

    -P.S.U, I have no idea what that could mean.

    On the right we have three unknown connectors and pots for adjustment.

    Mostly a mystery other then the data I can partially read from the nameplate, they also have 24VDC breaks.


    The only thing that I've concluded from these is that they are absolute encoders. As well, no documentation.

    I figured I would share. If anyone has any information or suggestions that would be appreciated. Other then that, I hope your having a nice day :D
  2. Dr.killjoy

    Well-Known Member

    Apr 28, 2013
    What is plans for these ????
    Is it possible to upgrade and rewire everything????
  3. panic mode

    Senior Member

    Oct 10, 2011
    PSU = Power Supply Unit (P = positive, N=negative)

    I work with robots (Kuka, Fanuc, ...) but not Nachi.

    My recommendation is to join
    also there is a Nachi section
    Last edited: Oct 31, 2013
  4. shredability

    Thread Starter Member

    Apr 1, 2012
    Thanks, this is much help. I'm assuming that were talking DC considering we got 100VAC at the top?
  5. shredability

    Thread Starter Member

    Apr 1, 2012
    Anything's possible, any yeah, that's the plan.
  6. strantor

    AAC Fanatic!

    Oct 3, 2010
    I see pain and anguish in your future, and likely a divorce or other flavor of disownership. I'm not saying you can't do it, but if you're not familiar with the acronym PSU, then you have a long, rough, nearly vertical road ahead you. Sizing servo drives can be a pain in the cojones even for seasoned professionals. Plan on buying way more (seriously expensive) parts than you'll end up using, and rendering some of them inoperable.

    Now that I've gotten that out of the way, how can we help? do you have a specific question? Where would you like to start?

    Disclaimer: I'm not a robotics guy, but I have played with similar (Kuka) robots a little bit, and played with some servos (limited servo experience). I work with motor controls as a day job, but my cup 'o tea is more horsepower and less inch-pounds. Ask away, but don't expect a whole lot. I'll help to the extent I'm able.
  7. shredability

    Thread Starter Member

    Apr 1, 2012
    What is comes down to is where to find documentation, or how to discover the pin functions. One I know this information I should be good.