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  1. #1
    Join Date
    Jun 2006
    Posts
    170

    Fanuc OM stuck in MDI mode

    We were running a program and out of the blue the machine shut down and went to MDI mode.... Turning the mode selector does nothing. Cant get the machine to move. Tried entering a program in MDI which i can do. Went to send it home but i had powered the machine down and its first move was rapid down. Now the cutter is 2 " from the table and i dont have a clue what to try next.

    Need help....i have jobs that are backing up now...

  2. #2
    Join Date
    Feb 2009
    Posts
    6028
    Usually stuck in MDI means you lost a power supply, or something is emergency stop. The Z probably fell due to the brake releasing, not actually being driven down.

  3. #3
    Join Date
    Jun 2006
    Posts
    170
    Quote Originally Posted by underthetire View Post
    Usually stuck in MDI means you lost a power supply, or something is emergency stop. The Z probably fell due to the brake releasing, not actually being driven down.
    It did seem to fall with a greater speed that i was expecting since rapid over ride was turned way down..

    In the process of checking for a blown fuse somewhere..

  4. #4
    Join Date
    Jan 2011
    Posts
    0
    Try to MID G-28 X0 Y0 Z0,and send it home slowly... when you at home reset your program to G01 or slow down on your rapic to 50% or 25%.if this work ,you should change your G00 from the begin of the program to F 50 ...you may get the short some where in power supply...check you 24V power supply 80% duw to 24V power supply. this case you Z move servo power supply.
    good luck

  5. #5
    Join Date
    Jun 2006
    Posts
    170
    Can anyone tell me what a W.A. ascent switch is and where I might find it?

  6. #6
    Join Date
    Jun 2006
    Posts
    170
    Quote Originally Posted by WillieDo View Post
    Try to MID G-28 X0 Y0 Z0,and send it home slowly... when you at home reset your program to G01 or slow down on your rapic to 50% or 25%.if this work ,you should change your G00 from the begin of the program to F 50 ...you may get the short some where in power supply...check you 24V power supply 80% duw to 24V power supply. this case you Z move servo power supply.
    good luck
    G28 Z0 sent it down at full rapid....i am now down to a Z overtravel and 1 " from the table.. and i nearly crappped myself when it went down..

  7. #7
    Join Date
    Jun 2006
    Posts
    170
    and it cant be the brake because it didnt move with feed rate turned down to zero...only when i turned it up....but it was definately under rapid because i only moved the feed rate to 10%

  8. #8
    Join Date
    Jun 2006
    Posts
    170
    the reason i asked about the WA switch is because there is a rely on my back panel door that has a red light on it. From the ladder diagram it is the relay for that switch. I dont know if a red light means anything on the relay but red is never really good

  9. #9
    Join Date
    Jun 2006
    Posts
    170
    also, any suggestions on how to get the Z axis up of the over travel limits....since the switch is stuck in MDi i cant use the handle and bypass switch... and i would rather not try any more G28 Z0 moves...

  10. #10
    Join Date
    Mar 2003
    Posts
    2932
    Quote Originally Posted by kirby View Post
    also, any suggestions on how to get the Z axis up of the over travel limits....since the switch is stuck in MDi i cant use the handle and bypass switch... and i would rather not try any more G28 Z0 moves...
    Can you get at the Z axis ball screw? In the old days... we used to power down the machine and turn the ball screw by hand to raise the head. That was before brakes, though.

    It's possible that when you did the G28 Z0 you were in absolute mode. It's usually safer to do G91 G28 Z0.

  11. #11
    Join Date
    Jan 2011
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    0
    Quote Originally Posted by kirby View Post
    also, any suggestions on how to get the Z axis up of the over travel limits....since the switch is stuck in MDi i cant use the handle and bypass switch... and i would rather not try any more G28 Z0 moves...
    Kirby
    G28 Automatic return to reference point, should send your machine home,check your setting swich on Absolute or Incremental, manual bypass over travel by get some one press and hold your Z over travel limits and slowly move the handle on Z out of travel limits if your bypass do not work.
    Can You move Home one Axis at the time?how old is your machine? older machine have the swich turn to Absolute or Incremental..? doulble check that...I can tell you more what to do if I know how olad is your machine!

  12. #12
    Join Date
    Jun 2006
    Posts
    170
    Quote Originally Posted by WillieDo View Post
    Kirby
    G28 Automatic return to reference point, should send your machine home,check your setting swich on Absolute or Incremental, manual bypass over travel by get some one press and hold your Z over travel limits and slowly move the handle on Z out of travel limits if your bypass do not work.
    Can You move Home one Axis at the time?how old is your machine? older machine have the swich turn to Absolute or Incremental..? doulble check that...I can tell you more what to do if I know how olad is your machine!
    It wont let me do anything till i clear the alarm and the alarm cant be cleared till i move off the limit switch. I cant move it by handle and i couldnt move it by the handle before it hit the switch... I am going to have to try to move it up by turning the leadscrew...

  13. #13
    Join Date
    Jun 2006
    Posts
    170
    Quote Originally Posted by dcoupar View Post
    Can you get at the Z axis ball screw? In the old days... we used to power down the machine and turn the ball screw by hand to raise the head. That was before brakes, though.

    It's possible that when you did the G28 Z0 you were in absolute mode. It's usually safer to do G91 G28 Z0.
    I can get at the screw and it does turn...when it get it up far enough i will try adding the G91..

  14. #14
    Join Date
    Jun 2006
    Posts
    170
    it wont clear the alarm even though its clear of the switch by 6 "

  15. #15
    Join Date
    Feb 2009
    Posts
    6028
    Quote Originally Posted by dcoupar View Post
    Can you get at the Z axis ball screw? In the old days... we used to power down the machine and turn the ball screw by hand to raise the head. That was before brakes, though.

    It's possible that when you did the G28 Z0 you were in absolute mode. It's usually safer to do G91 G28 Z0.
    I agree, always use a G91 with a ref return. I still think you lost a power supply, probably next to the CRT. That power supply controls the operator panel, so switches, knobs and overrides don't work.

  16. #16
    Join Date
    Jun 2006
    Posts
    170
    Quote Originally Posted by underthetire View Post
    I agree, always use a G91 with a ref return. I still think you lost a power supply, probably next to the CRT. That power supply controls the operator panel, so switches, knobs and overrides don't work.
    I am with you on the G91...lol. 2 rapid plunges straight down with a $300 cutter in the spindle made me a believer...

    And i know its going to sound stupid but my mind isnt working clear....what and where is the CRT ?

  17. #17
    Join Date
    Feb 2009
    Posts
    6028
    The screen. Not totaly sure about your machine in particular, but a lot of older Fanucs had a power supply board up in the operator panel area. And make sure something is not overlooked like a panel key switch or something. Had a daewoo do something just like your describing.

  18. #18
    Join Date
    Jun 2006
    Posts
    170
    display screen...lol google knows all... i am looking for a fuse or power supply box but i see nothing..

  19. #19
    Join Date
    Jun 2006
    Posts
    170
    Quote Originally Posted by underthetire View Post
    The screen. Not totaly sure about your machine in particular, but a lot of older Fanucs had a power supply board up in the operator panel area. And make sure something is not overlooked like a panel key switch or something. Had a daewoo do something just like your describing.
    The nut on my rapid over ride switch backed off just before this happened. It was moving pretty free and my operator gave it a few good twists. I looked for a broken wire but cant find any. Normally it has been my experience that 2 random things rarely happen at the same time...they are usually related. I just need to figure out how..

    Also it is an older machine, a Kiwa Excel Mustang circa 1991...

  20. #20
    Join Date
    Jun 2006
    Posts
    170
    i think i found a broken wire to that switch.... cant find where it came from but there is a wire there for sure.. it seems to be coming up from the coolant on off switch which is just below it..

    i am not good at electronics and electrical so i cant see why it would be connected..it is soldered to a terminal with another wire on the coolant switch..could it be power in a sequence from one switch to another??

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