How to start the robot motors after I close the door using the PLC HMI panel

    Hello, I have a problem that if I open the door that is on the cell and then after closing and confirming the security, the robot does not start further in the cycle. However, if I manually start the drives in the SIR line, it continues without any problems. With the help of the PLC, I can confirm all error messages, but I cannot start the robot further into the cycle.

    The robot works for me in an automatic cycle according to the requirements, I just want to make it move only with the help of the RESET button on the HMI.

    I will be grateful for any advice and thanks in advance

    Robot: KR120R2700
    KRC5
    KSS 8.7.5

  • Fubini June 4, 2024 at 11:26 AM

    Approved the thread.

    read the manual...

    to run robot:
    a) program need to be selected
    b) messages need to be acknowledged,
    c) drives need to be on and
    d) start need to be issued.

    last three points (b/c/d) depend on mode.

    there are 4 modes. T1/T2/AUT/EXT

    in first three modes (T1/T2/AUT), it is the user that runs the robot (does acknowledging of messages, powering drives and issuing start.

    in EXT mode, PLC does those actions.

    so... you are using robot in a wrong mode.

    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

    Edited once, last by panic mode (June 4, 2024 at 3:24 PM).

    Assuming your robot is in EXT mode, the signal sequence to start the robot from the PLC is, basically:

    1. $DRIVES_OFF and $MOVE_ENABLE held True
    2. Pulse $CONF_MESS until $STOPMESS is False
    3. Pulse $DRIVES_ON until $PERI_RDY is True
    4. Pulse $EXT_START until $PRO_ACT is True

    These steps need to be carried out in this sequence.

    Thanks for the advice, I tried to follow your advice exactly, but after implementing it, after switching the robot to EXT AUT, drives turn off, PERI_RDY is thrown and STOPMESS remains TRUE. If I try to turn on drives manually, the signals start to beat and DRIVES_ON and PERI_RDY flash. STOPMESS is set to FAULSE only in T1 if I press deadman.

    However, the robot already worked fully for me in EXT AUT, only if I open the door and break the safety circuit, I can't get the robot back into the cycle, I manage to confirm all the error messages via the reset button on the HMI, but I don't get PERI_RDY and the robot doesn't move.

    That's why I'm turning to you once again with a request for advice, because even what was going on up to this moment is no longer working for me.

    Edited once, last by Jakub2210 (June 5, 2024 at 9:16 AM).

    Quote from Jakub2210

    So the problem was that I didn't have DRIVES_OFF mapped correctly, as soon as I mapped it to IN[1025] it works exactly as I wanted

    That doesn't sound right. If $DRIVES_OFF was improperly mapped, the robot should have never worked correctly in EXT mode. I suspect the issue is in your PLC code.

    However, mapping $DRIVES_OFF to $IN[1025] should work well enough. I would check the PLC code to be sure that $DRIVES_OFF wasn't being used for anything critical, however.

    I checked the PLC code and found nothing where $DRIVES_OFF is used so that the use is critical. The error was also in the PLC code and in the bad mapping. Now it works as I wanted and there are no errors, the robot moves after closing the door and confirming all the necessary safety.

    no...!

    standard and safety signals are two completely different things...


    SAFETY signals are there to protect human life and limb (prevent human injury or death). they are there to prevent spilling of the blood which is why safety devices are typically colored red or safety yellow... that includes relays, sensors, light curtains, everything... even programming window, IO and configuration screen are highlighted in safety colors. safety signals are redundant, monitored and wiring/installation must be done in a way to make defeating/bypassing impossible or at least as difficult as possible.


    STANDARD signals are used for everything else... and among other things they may include detecting/preventing situations that could cause equipment damage. standard signals/devices/terminals/connections/logic etc are NOT colored red or safety yellow. they are sometimes referred to as "gray logic" etc.


    opening cell door disables robot... but... this is (must be) done by a safety circuit, and this must work, irrespective of move enable. because move enable is not a safety rated signal. it is a standard input. this is one option to allow PLC to stop robot at will, any time, and automatically - that means without need for user action (such user opening cell door).

    so move enable is meant to disable robot when one of user defined abnormal conditions is encountered and PLC is (can be made) aware of the problem. you need to program those conditions. for example ... could be things like tool damage (broken gripper or drill or cutting tool), part not located correctly (becomes free/lose), something unexpected is causing interference or blocking sensors, welding wire stuck, etc. this could be a very long list. and it may save tons of downtime, prevent equipment damage etc. but it is not rated or expected to protect humans.

    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

    Of course, I also have safety devices attached to the door, the PLC programmer wouldn't even let me open it without the necessary configuration of the safety elements, and I wouldn't allow it myself. I have everything linked to safety and I don't have to use only standard signals. I pay attention to safety and I probably expressed myself badly and said it too simply. Safety is done according to standards and I can't even afford to bypass it because I am fully aware of the possible consequences.


    After opening the door, operator safety falls and the air in the entire cell is turned off, the motors brake and the drives go to 0 until I confirm safety, and only then does the robot move at all, without safety the robot always has its drives turned off.

    Edited once, last by Jakub2210 (June 11, 2024 at 10:14 AM).

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