Skip Signal


Results 1 to 11 of 11

Thread: Skip Signal

  1. #1
    Registered
    Join Date
    Aug 2007
    Location
    uk
    Posts
    58
    Downloads
    0
    Uploads
    0

    Default Skip Signal

    Hi All,

    I have tested the skip I/P with a simple micro switch and the G31 functions correctly with a simple program... so I'm now writing a macro for a tool setter.

    Generally the macro design is within the power of my brain cell, just.... but I'd like to verify that the signal from the probe is going On - Off - On as expected as the tool touches retracts and touches again for the final "read".
    If the probe is open / closed at the wrong time, then a #3006=1 (probe fail) would abort the setting routine and flag an alarm.

    But,
    I can't find in the Fanuc manuals (no surprise there ) how to read the status of the skip signal (or any of the general I/O).

    Any help / points would be a great help.
    Cheers
    Derek.

    Similar Threads:


  2. #2
    Community Moderator Al_The_Man's Avatar
    Join Date
    Dec 2003
    Location
    Canada
    Posts
    23376
    Downloads
    0
    Uploads
    0

    Default

    The skip input cannot be made conditional so it does not show up in the ladder AFAIK.
    When writing G31 routines or macro's it is customary to have a protected positioning move, this is a routine that would typically be used to move the probe to initial position in say rapid, IOW, any move of the probe should include a G31.
    The standard G31 input is sent from PLC to CNC via the BMI, an optional High speed skip input is available through an add on board and option parameter that directs the high speed G31 skip input directly to the CNC side.
    Al.

    CNC, Mechatronics Integration and Custom Machine Design

    “Logic will get you from A to B. Imagination will take you everywhere.”
    Albert E.


  3. #3
    Registered
    Join Date
    Aug 2007
    Location
    uk
    Posts
    58
    Downloads
    0
    Uploads
    0

    Default

    Hi Al,

    I've been thumbing through the manual -
    It says that the input interface signals 1 to 32 can be read by variables #1000 to #1031.
    I'm hoping that the skip x4.7 is connected to one of these i/ps
    I haven't got the electrical drawings with me, so I'll have to check when I get to work tomorrow.

    I just want to check the probe closes on the back off move...just a bit of error checking realy, or that the tool hasn't mashed the tool setter ;-)

    I wasn't sure if i could use a G31 with a G0 - I'll give that a try too.

    ATB



  4. #4
    Member
    Join Date
    Sep 2010
    Location
    Australia
    Posts
    1227
    Downloads
    0
    Uploads
    0

    Default

    Quote Originally Posted by derekBPcnc View Post
    Hi Al,

    I've been thumbing through the manual -
    It says that the input interface signals 1 to 32 can be read by variables #1000 to #1031.
    I'm hoping that the skip x4.7 is connected to one of these i/ps
    I haven't got the electrical drawings with me, so I'll have to check when I get to work tomorrow.

    I just want to check the probe closes on the back off move...just a bit of error checking realy, or that the tool hasn't mashed the tool setter ;-)

    I wasn't sure if i could use a G31 with a G0 - I'll give that a try too.

    ATB

    I wasn't sure if i could use a G31 with a G0 - I'll give that a try too.

    No you can't. G31 is a one shot command that is terminated by the slide reaching the end point or by the change of state of the switch, and functions similarly to G1. Accordingly, if you want rapid movement in the G31 block, include a fast feed rate.

    I just want to check the probe closes on the back off move...just a bit of error checking realy, or that the tool hasn't mashed the tool setter ;-)
    You have the logic correctly planned. The switch should be made when the tool/probe is in fresh air. A broken wire etc in the system will therefore fail safe.

    Regards,

    Bill

    Last edited by angelw; 11-13-2011 at 03:14 PM.


  5. #5
    Member
    Join Date
    Sep 2005
    Location
    USA
    Posts
    767
    Downloads
    0
    Uploads
    0

    Default

    There are macro inputs and outputs that you can see with variables in the 1000s, but those are not related to the SKIP input. I suppose you could wire your probe output to BOTH the SKIP input and one of those 16 user macro inputs (Ui0-Ui15), but that may corrupt the latency of the SKIP input. These macro inputs have to be processed in the ladder, so if your ladder doesnt' have them, you may have to modify the ladder as well as wire up the extra input.

    I suggest this trick instead: If you want to check if the probe is stuck on, move to a position where you know the probe be off, save the current absolute position in a local variable, then make a very short G31 move to another point where the probe should also be clear. If the SKIP axis position is not the same as the "target" position, then the probe is stuck, and you should generate an alarm. I used to do it this way when we were digitizing with Renishaw MP1 probes. They liked to stick in the "on" position when you move away after touching the part. I believe we even went to the extra effort to "bounce" the probe against the last known part surface, then back away again to center the probe, rather than throw an alarm. When you're touching 10,000 points in a digitizing cycle, you've got to have some way to recover from a stuck probe.



  6. #6
    Registered
    Join Date
    Aug 2007
    Location
    uk
    Posts
    58
    Downloads
    0
    Uploads
    0

    Default

    Hi Dan, Bill

    Thanks for the replys.

    The Fanuc manual says that #1000 to #1031 can be used to read the status of the external inputs.
    trying to read anything over #1015 cause a variable out of range error, so ties up with what you say about Ui0 to Ui15.

    I thought that the input registers would be mapped to the #1000 variables - obviously not the case (and outputs to # 1100 - #1131 I think).

    SO - I'll take your advice and use some logic comparing the absolute position before and after skip to make sure the expected move has been made and not 'halted' by a stuck probe (tool setter stylus).
    As a side note - I see andthe X4.7 Skip in the PMC maintenance status screen and it toggles when the probe is tripped- I guess that the X4.7 signal is not being passed to the CNC...but it must be for it to process the G31 command ...that's the confusing part.

    The other way I was going to try to extract the status of skip signal was to read the whole of the X4 register and process that Byte to extract BIT7 - I think #1032 to #1035 reads the whole register??? IF that can be done in Fanuc (I'm thinking microprocessor register techniques, so might be complete tosh when it comes to CNC

    I haven't seen the Renishaw macros, so I dont know how Renishaw error check probe open / stuck to flag an error.

    Fun learning if nothing else :-)

    ATB
    Derek



  7. #7
    Community Moderator Al_The_Man's Avatar
    Join Date
    Dec 2003
    Location
    Canada
    Posts
    23376
    Downloads
    0
    Uploads
    0

    Default

    Quote Originally Posted by derekBPcnc View Post
    As a side note - I see andthe X4.7 Skip in the PMC maintenance status screen and it toggles when the probe is tripped- I guess that the X4.7 signal is not being passed to the CNC...but it must be for it to process the G31 command ...that's the confusing part.

    ATB
    Derek
    As I mentioned, the PMC skip is passed over to the CNC side via the BMI. Basic Machine Interface, this is the bus that the CNC and PMC talk to each other, normally the PMC and the CNC communicate via G and F registers, it is a while since I implemented a Fanuc ladder, but I believe there is no G register bit available to enabling conditioning the Skip input, the High Speed skip bypasses the BMI/PMC and inputs direct to the CNC.
    Al.

    CNC, Mechatronics Integration and Custom Machine Design

    “Logic will get you from A to B. Imagination will take you everywhere.”
    Albert E.


  8. #8
    Member
    Join Date
    Feb 2006
    Location
    india
    Posts
    1770
    Downloads
    0
    Uploads
    0

    Default

    Quote Originally Posted by derekBPcnc View Post
    ...
    The Fanuc manual says that #1000 to #1031 can be used to read the status of the external inputs.
    trying to read anything over #1015 cause a variable out of range error, so ties up with what you say about Ui0 to Ui15.

    I thought that the input registers would be mapped to the #1000 variables - obviously not the case (and outputs to # 1100 - #1131 I think).

    ...
    #1000 - #1015 and #1032 are defined.
    #1016 - #1031 may not be defined.
    The same applies to output signals also.
    See the attachment for more details.

    Attached Thumbnails Attached Thumbnails Skip Signal-interface-signals-pdf  


  9. #9
    Member
    Join Date
    Jul 2006
    Location
    USA
    Posts
    65
    Downloads
    0
    Uploads
    0

    Default

    Quote Originally Posted by Dan Fritz View Post
    I suggest this trick instead: If you want to check if the probe is stuck on, move to a position where you know the probe be off, save the current absolute position in a local variable, then make a very short G31 move to another point where the probe should also be clear. If the SKIP axis position is not the same as the "target" position, then the probe is stuck, and you should generate an alarm.
    Here's a quick sample prg of that same concept.

    O9032(REN FLASH ON)
    G98

    #2=#5042-#5082
    #3=[#2-[.002]]
    #4=0
    N2
    IF[#4GT4]GOTO4
    G31Z#3F20.
    G4U.1
    #6=#5042-#5082
    G4U.1
    IF[#6LT#2]GOTO5

    G0Z#2

    M55
    G4U.7
    M54(M CODE TO TURN PROBE ON)
    G4U.7
    M55(RESET M CODE)

    #4=#4+1
    GOTO2
    N4
    #3000=101(PROBE START UP FAILURE-CHECK BATTERY)
    N5
    G0Z#2
    M99



  10. #10
    Registered
    Join Date
    Aug 2007
    Location
    uk
    Posts
    58
    Downloads
    0
    Uploads
    0

    Default

    Quote Originally Posted by sinha_nsit View Post
    #1000 - #1015 and #1032 are defined.
    #1016 - #1031 may not be defined.
    The same applies to output signals also.
    See the attachment for more details.
    Hello Sinha,

    Thanks for the info - I'll 'digest' in conjunction with the manual tomorrow when I'm back in the office, as I understand now, that X4.7 skip is not mapped to a user variable.:-(
    Another quick question - of the variables in the range #1000 to #1015 - how do I work out the mapping of a specific input (say X2.1) to a particular variable?
    -------------------
    Hi Dan,
    Thanks for the section of code- looks like a plan is forming
    I got the MI-8 interface delivered today -so let the real fun commence

    ATVB
    Derek



  11. #11
    Member
    Join Date
    Feb 2006
    Location
    india
    Posts
    1770
    Downloads
    0
    Uploads
    0

    Default

    Quote Originally Posted by derekBPcnc View Post
    ...Another quick question - of the variables in the range #1000 to #1015 - how do I work out the mapping of a specific input (say X2.1) to a particular variable?
    Read the attachment which has more detailed information.

    Attached Thumbnails Attached Thumbnails Skip Signal-interface-signals-details-pdf  


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
  •  


About CNCzone.com

    We are the largest and most active discussion forum for manufacturing industry. The site is 100% free to join and use, so join today!

Follow us on


Our Brands

Skip Signal

Skip Signal

Skip Signal