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ACC - Global Variable - does such exist?

  • Hello guys,

    I need a small help.

    How to globally increase robot speed? I've checked already variable list and description of each and had found variable like below:


    $CMSCH[1].$nom_acc_ovr

    Minimum: 0.001 Default: 1.0 Maximum: 5.0
    KCL/Data: RW Program: RW GET/SET_VAR: RW Data Type: REAL

    Name: Intellitrak Global Accel Override

    Description: This variable is a global acceleration override that affects the entire program. The default value is 1.0 which means the default acceleration time is used. A value of 0.8 means acceleration time is
    0.8 * default acceleration.

    Power Up:

    User Interface Location: SYSTEM Variables screen


    Problem is, variable is not existing any more in Fanuc Variable System List. Instead mantioned above, I found ACC_MAXLMT 100. Is it the same variable?

    My major question is, how to globally change the robot speed (100% is to less ;) ). If I will use ACC_MAXLMT 125, then I have to change almost each line in 8 progs. How to avoid that?


    I would be grateful for any help ;)


    Greets

  • There is an ACC motion option that will decrease your acceleration/deceleration time, but there are many things you should check before increasing ACC above 100:


    1. Is your payload set correctly?

    2. Is your motion optimized? (i.e. is it traveling along the shortest possible path)

    3. Is your motion smooth? (use CNT100 wherever possible and avoid FINE if possible)

    4. Is the robot waiting unnecessarily?

    5. Are your motion segment speeds set appropriately?


    FANUC actually added the ACC option to allow customers to slow things down (sub-100 ACC-values) and eventually set the default maximum ACC to 100 because of frequent abuse.

  • Hello again, and sorry for late response,


    jay all 5 mentioned points are correct, my problem is related to Fanuc 2000iB with R-30iB controller.


    In one cell I've got 2 screwing robots, conveyor in betweem them. I try to understand why one of them is visibly slowest than the other, if the programs are mirrored. Each of them has 4 operations, movements with CNT100, but one is slower round 300ms each segment (what in 50sec cycle time is much for me).

    If you know the reason, you know where I have to check, and what I have to check, I would be grateful for answer. Only few days left to start the line, and this issue annoying me much.


    Thx in advance for any replies, of corse in case of any questions please let me know ;)

  • When two identical robots are running the same program and one is visibly slower, it's usually a payload issue e.g. one robot is accidentally using the default max payload while the other has the payload set to something lower.


    Barring that, maybe one robot is using Cycle Time Priority and the other is using Path Priority? (Controlled start, Menu > Maintenance > Manual)

  • jay , thx a lot for advice.

    Payload is exactlu the same for both of them, but mentioned CTP or PP I will check today evening.

    Will let you know, if I find something ;)

    THX

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