slow robot in automatic mode

    Hello all,

    I am programming a second hand M3ia 6A delta robot with a R30iA mate controller.

    I've set all the J movement speeds to 100% and the L movement speeds to 10000mm/sec.

    That robot should really fly, but it i moving super slow, there is difference from T1, but not that much.

    Being a secondhand robot, lots of things can be modified...

    Where would you search for the reasons of that?

    - I've seen $MCR.$GENOVERRIDE was at 10, changed it to 100, but the behavior is the same.

    - The $MCRGRP.$MCR_GRP[1].$PRGOVERRIDE value is 100.

    - OVERRIDE SELECT (MENU -> SETUP -> OVRD SELECT) function is disabled.

    - there is a payload of 0.2kg.

    - If I check the web server from my edge browser, Under safety Status Information I can see HAND BROKEN is TRUE, even the $HBK_ENBL variable is FALSE.

    Is something else I should look for?

    Notice: I have no clue of what this robot is capable to do in terms of real speed, it is moving a very light load and delta robots are super fast usually... It's an impression only, but at those speeds it takes 5 seconds to pick a part and leave it over a distance of 1meter +/-. The cycle is the usual one in those cases:

    J HOME 100% CNT0.

    J approach the calculated pick part position speed 100% CNT0.

    L get in touch with the part 10000mm/sec FINE.

    L CNT0 go back to the approach position 10000mm/sec CNT0.

    J HOME 100% CNT0.

    J approach the part placing position speed 100% CNT0.

    L Placing position 10000mm/sec FINE

    J approach the part placing position speed 100% CNT0.

    And start again.

    Any idea or hint to what should I look for?

    I won't have access to the robot this weekend, but I will have a copy of the md FTP folder at home.

    Thank you in advance for your time and help.

  • Go to Best Answer

    Looks like you are using CNT0, try upping those. CNT0 moves are pretty close to fine moves so the robot is going to be accelerating and decelerating a lot between each move, if the points are close together it won't have the opportunity to move fast. If you don't need the accuracy a CNT100 move is going to be much faster. Usually I use CNT100 for open air moves and like 1 move before a fine move for a pick I'll switch to somewhere around CNT10. But if you need accuracy to get into tight spots or to avoid things you'll need to keep your CNT value low.

    If you want a fanuc robot to run smoothly and fast, do not use CNT less than 80... on pick and place aplications with suction cups you may need to use CNT on the picking point instead of FINE while using a DB (distance before) instruction to activate and deactivate the suction signals while moving.


    I always program with cnt100, only when approaching a zone where I have tight space I reduce it to 80, and then before reaching the workpiece, if I need it, then I lower it to CNT50.

    You may need to add a few more points using cnt100 far apart from the zone in order to allow the robot to get speed while traversing without colliding with something.

    As rule of thumb, at least on 6 axis robots you should try to keep the cnt at 100 while you can.

    Old robots with RJ3 controllers are tricky since they can change the path when changing override, on new controllers its not very noticeable. Just make sure to try the path on T1 if you change CNT or % speed because path will change even if you only increase 10 units the cnt values.

    OK, changed the CNT values to 25, 50 and 100 and this has made an enormous difference.

    Coming from ABB and KUKA, I am used to specify the movement speed and then the radius of the approximation to points, and the latter usually has no effect in the travel speed (even you can see the robot to accel and decel).

    After having changed all that, I've set up the speed to a Register to be able to update all movements at once. Oh, and I've went from 10000mm/sec to 1500mm/sec and even like this the robot is making all the machine shake like there is no tomorrow now...

    Well, nothing to see here, thank you all for your time and help!

    allWar No PLC here. Thanks anyway.

    • Best Answer
    Quote from robotecnik

    OK, changed the CNT values to 25, 50 and 100 and this has made an enormous difference.

    Coming from ABB and KUKA, I am used to specify the movement speed and then the radius of the approximation to points, and the latter usually has no effect in the travel speed (even you can see the robot to accel and decel).

    After having changed all that, I've set up the speed to a Register to be able to update all movements at once. Oh, and I've went from 10000mm/sec to 1500mm/sec and even like this the robot is making all the machine shake like there is no tomorrow now...

    Well, nothing to see here, thank you all for your time and help!

    allWar No PLC here. Thanks anyway.

    Take care with modifying the speed using a registers.

    This is fanuc, override affects the robot path.

    Only way to ensure your robot will repeat the same path every time when changing speeds is to have an additional option called "Constant Path"

    If not, general override, speed and cnt will affect the path.

    With payload I have not seen difference, but the robot warns you every time you change the payload data that path can change...

    ABB and kuka have the "Corner region", Fanuc have this same option but you need to puchase the corner region option (it's another more option)

    If you have the option you can use the "CR" termination type, instead of the "CNT"... it's like the zone from ABB (but it's only avaiable on linear moves)

    CNT reffers to "continuous" and it behaves very different from ABB or Kuka...

    When starting from a fine point you usually can use a CNT100, but when approaching the destiny you will need to decrease the CNT value.

    And if you want a fanuc to be fast, you often need to add points very far apart from the workpieces (with CNT100 if possible) in order to allow the robot to trim the trajectory while maintaining speed without colliding with obstacles.

    Joint movements usually trim more the path than linear movements, also OLD controllers like the "RJ3" trim very much the path and override affects them much more than on newer controllers (not on every mechanical unit, but I found drastic differences on robots with longer Axis 3 arms)

    Changing "General override" on new controllers, the path difference is not very noticeable, but for sure if you change the speed with registers you will see a big difference... take care with that and if you want to do that, first make sure to run the robot probram at least one cycle at low speeds.... if on T1 works well you will likelly not have problems on automatic.


    Note: Increasing the speed of movements is not always beneficial, if you have a lot of points very close each other, the most probable scenario is that robot will run slower with speed "5000mm/s" than with speed "2000mm/s".

    This has a reason, robot needs to get speed, if you put a lot of speed on the motions, the robot will be accelerating and deccelerating continuously losing preious time and increasing the wear on the mechanical unit.

    The motion planers often optimizes this, but sometimes it's not the case and you will see that robot moves faster with lower speeds....

    Edited once, last by Shellmer (March 20, 2023 at 11:53 PM).

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