Distance between effective robot work enveloppe and light curtains

    Hi everybody,

    I have an industrial application in which an operator needs to be able to manually load a support so that the robot can pick up these parts.

    When the operator is in the exchange zone (outside the robot zone), I apply a speed reduction to the robot via SFDI, using the Cartesian Position Check Speed Check (let's say 30% override).

    I've created a DCS zone on the operator/robot exchange table.

    We want to install a light curtain that triggers an emergency stop if the robot is in the table zone and the light curtain is triggered. In a way, the robot is forbidden to go into the table zone, but if it does go there, the DCS stops the robot if the operator is loading a part, i.e. the light curtain is triggered.

    I'd like to know what minimum distance we need to put between the table and the light curtains, given that my robot speed is safely reduced to 30% override. Is there a formula?

    P.S : The robot is a M20id25.

    Thank you in advance,

    Paul

    The distance would be from the edge of the DCS zone to the light curtain plane. You would need to calculate the stopping distance off the robot and the total reaction time and hand/finger penetration depth between light curtain beams. The complete formula would be:


    RobotStopDistance + (63in/s X TotalReactionTime) + DepthOfHandPenetration.


    The 63in/s represents a fast human hand.


    Your distance is likely going to be large enough that a person could stand inside the light curtain. In that case you need to protect both vertically and horizontally with 2 light curtains or sometimes you can get by with 1 mounted at a slant.

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