Robot speed monitoring

    Hi all,

    I have KUKA KRC2 with Version V5.5.16.

    Inverters (variable frequency drive) - Hitachi makes

    We are trying to achieve a simultaneous speed change between the robot and the inverter.

    Condition:

    A Rockwell PLC is used to control the process using a KUKA robot and 3 inverters. Considering we are increasing the override speed from 30% to 50% in the robot, we need this change to increase the speed of inverters proportionally and simultaneously.

    Alternatively, is it possible to use the PLC to control and alter the robot's speed, i.e., to alter the robot's speed concurrently by increasing the inverter speed?

    Is this a condition that can be attained? Which one, if any, would be a wise decision?

    Please offer your thoughts and recommendations.

    cheers .:beerchug:

    • Best Answer

    if i understand correctly, PLC controls three Hitachi drives and at the same time it is connected to KRC.

    you wish to make adjustments of the robot speed override and want PLC to know the value of the override so that it can do the same speed correction with the Hitachi drives.

    to do that, map override to robot outputs that PLC can read, then do whatever you need in the PLC end.

    the override range is 0-100 so 7bit would be sufficient (for example outputs 151-157 if they are free to use and in range that PLC can read).

    so in the KRC\R1\$CONFIG.DAT declare signal

    Code
    SIGNAL OV_TO_PLC $OUT[151] TO $OUT[157]

    and in Submit program (KRC\R1\SPS.SUB), in the user fold (inside LOOP/ENDLOOP) add line such as

    Code
    OV_TO_PLC = $OV_PRO

    on the PLC side do the same but the other way - copy value of those 7 PLC inputs into a variable and use it any way you like (scale it etc.).

    1) read pinned topic: READ FIRST...

    2) if you have an issue with robot, post question in the correct forum section... do NOT contact me directly

    3) read 1 and 2

    Thanks Panic mode for the detailed reply.

    Quote

    map override to robot outputs that PLC can read, then do whatever you need in the PLC end.

    the override range is 0-100 so 7bit would be sufficient (for example outputs 151-157 if they are free to use and in range that PLC can read).

    I followed the steps you provided and successfully mapped the override to robot output.

    I got another thought that,

    Is it possible to change and control the speed of the robot using the plc ? ( just the opposite of what we have discussed )

    ie,

    I wish to make adjustments to the Hitachi drives using PLC and want robot to know the value of the speed changed so that it can do the same speed correction.

    Please share your thoughts

    cheers

    Sure .. pretty much the same thing, just in reverse.

    Scale velocity of drives to 0-100 percent and copy the result to PLC outputs that robot can read. On the robot side declare suitable signal with correct range of inputs. In the submit, copy received value from that signal to suitable variable like $OV_PRO. Personally i am really really not fan of that. User should always be able to reduce speed... Of course there is always an e-stop but that is too brute imho

    1) read pinned topic: READ FIRST...

    2) if you have an issue with robot, post question in the correct forum section... do NOT contact me directly

    3) read 1 and 2

    Thanks Panic mode for the valuable feedback.

    Quote

    Personally i am really really not fan of that. User should always be able to reduce speed

    I understood the safety issue due to that. I just asked out of my curiosity and I tried reversing the commands as you said. It works fine.

    Thanks again and have a great day.

    So sorry I cant find the link "KRC\R1\SUBMIT.SUB"

    I check the program and in KRC\R1\System\$CONFIG.DAT, i see that the declare

    INT DEF_OV_PRO=100

    SIGNAL go_297_Override $OUT[297]  TO $OUT[303]

    And in KRC\R1\System\sps.sub like the picture

    Robot not output the Speed Override via Output

    go_297_Override

    Pleae help!

    Thanks

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