525,667 active members*
2,381 visitors online*
Register for free
Results 1 to 4 of 4
  1. #1

    21-M Ladder editing enable

    Hi all,

    I recently acquired a mill with a 21-M control, and I need to edit the ladder program to enable g127.5 for DNC. Unfortunately the manufacturer did not provide a tape or remote switch, and the memory on this machine is very limited.

    This machine unfortunately did not come with the ladder edit option, and I have verified that the PMC module on the main card is the one without the edit option (A20B-2900-0143). I do have an edit-capable PMC module on hand from a prior retrofit (A20B-2900-0142). I have a couple questions regarding this swap:

    1.) Can this swap happen without consequence to the ladder program? My understanding is that the ladder program is in the UV EPROM (socketed), and thus is non-volatile. This leads me to believe that the PMC card is only for processing.

    2.) If I swap these cards to enable editing, does this mean I will have to enable a parameter? I am assuming that I would, but I am unsure (and I do not want to test until I find an answer to question 1!)

    Thank you for any help. This looks like a great machine, but sadly is in retrofit territory if I can't run a decent sized program.


  2. #2

    Re: 21-M Ladder editing enable

    Another question would be whether the G127.5 register could be written to directly? I know that the CNC communicates with the PMC via "F" registers (which could be an M code, for example), and then the PMC communicates back to the CNC via "G" registers.

    Is there a possibility that the G127.5 could be operated without the interaction of the PMC? I guess this might be a diagnostic bit? I have no official training here, so I'm just trying to figure out something that will make the machine usable.


  3. #3

    Re: 21-M Ladder editing enable

    Ohhhh boy. I just started digging through the diagnostics pages, and it looks like G127.5 is not even present. So I guess a super-secret parameter must be enabled in order to even have DNC capability?

    EDIT: Maybe that's not as big an issue as I thought. It seems that the Diagnostics pages will only contain the information that is in ladder currently; if G127.5 is not in ladder, it will not be in diagnostics either.

  4. #4
    Join Date
    Apr 2011

    Re: 21-M Ladder editing enable

    Try G43.5

Similar Threads

  1. editing ladder on fanuc 18i-t
    By achron in forum Fanuc
    Replies: 2
    Last Post: 11-16-2017, 06:27 PM
  2. ladder editing in 18m
    By periyanan.m in forum General Off Topic Discussions
    Replies: 0
    Last Post: 10-26-2015, 10:06 AM
  3. Ladder editing
    By sinha_nsit in forum Fanuc
    Replies: 9
    Last Post: 11-11-2009, 05:54 PM
  4. Ladder editing
    By luca_r in forum Mazak, Mitsubishi, Mazatrol
    Replies: 7
    Last Post: 06-05-2009, 09:02 AM
    By CHAD LAWSON in forum Fanuc
    Replies: 2
    Last Post: 01-30-2009, 01:36 PM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts