PROFIsafe

Description

The PROFIsafe network protocol (implemented as version 2.6.1) enables the robot to communicate with a safety PLC according to ISO 13849, Cat 3 PLd requirements.

The robot transmits safety-related information to a safety PLC and receives safety-related information from it.

Safety-related communications can be state messages or can trigger a safety function (e.g. reduced settings, stop).  Stop commands are described according to IEC 60204-1, where the emergency stop is a Category 1 stop and the safeguard stop is a Category 2 stop.

 

The PROFIsafe interface provides a safe, network-based alternative to connecting wires to the safety IO pins of the robot control box.

Using the PROFIsafe interface maintains the UR robot’s functional safety specifications (PL, category, and PFH). For details, see the “Safety Functions Table” section in the UR manual. For example, the “safeguard stop” is PLd Category 3 with a PFH value less than 1.8E-07 (1.8 x 10-7).

 

 
Safety PLC Out

A control message that the safety PLC sends to the robot contains the information shown in the following table.

Signal Description

E-Stop by system

  • 0: Asserts the system e-stop.

  • 1: Clear system e-stop.

Safeguard stop

  • 0: Asserts the safeguard stop.

  • 1: Normal operation state.

Note: Also refer to the “Reset safeguard stop” signal description.

Reset safeguard stop

Resets the safeguard stop state on a 0-to-1 transition when the “safeguard stop” signal is already set to 1.

Safeguard stop auto

  • 0: Asserts safeguard stop if the robot is operating in Automatic mode.

  • 1: Normal operation state.

Safeguard stop auto shall only be used when a 3-Position Enabling (3PE) Device is configured. If no 3PE Device is configured, the safeguard stop auto acts as a normal safeguard stop input.

Note: Also refer to the “Reset safeguard stop auto” signal description.

Reset safeguard stop auto

Resets the safeguard stop auto state on a 0-to-1 transition when the “safeguard stop auto” signal is already set to 1.

Reduced

  • 0: Activates the Reduced safety limits.

  • 1: Activates the “Normal mode” safety limits.

The safety system guarantees the robot is within reduced limits less than 0.5s after the input is activated. If the robot arm continues to violate any of the reduced limits, a Stop Category 0 is triggered.

Operational mode

  • 0: Activates the manual operational mode.

  • 1: Activates the automatic operational mode.

If the safety configuration "Operational mode selection via PROFIsafe" is disabled, this field shall be omitted from the PROFIsafe control message.

 
Safety PLC In

A status message that the robot sends to the safety PLC contains the information shown in the following table.

Signal Description
Stop, cat. 0

  • 0: Robot is performing, or has completed, a safety stop of category 0; a hard stop by immediate removal of power to the arm and the motors.

  • 1: Normal operation state.
Stop, cat. 1

  • 0: Robot is performing, or has completed, a safety stop of category 1; a controlled stop after which the motors are left in a power-off state with brakes engaged.

  • 1: Normal operation state.
Stop, cat. 2

  • 0: Robot is performing, or has completed, a safety stop of category 2; a controlled stop after which the motors are left in a power-on state.

  • 1: Normal operation state.
Violation

  • 0: Robot is stopped because the safety system has failed to comply with the active safety limits defined.

  • 1: Normal operation state.
Fault

  • 0: Robot is stopped because of an unexpected exceptional error in the safety system.

  • 1: Robot is not experiencing an unexpected exceptional error in the safety system.
E-stop by system

  • 0: Robot is stopped because of one of the following conditions:

    • A safety PLC connected via PROFIsafe has asserted a system level e-stop.

    • An IMMI module connected to the control box has asserted a system level e-stop.

    • A unit connected to the system e-stop configurable safety input of the control box has asserted a system level e-stop.

  • 1: Robot is not in system e-stop.
E-stop by robot

  • 0: The robot is stopped because of one of the following conditions:

    • The e-stop button of the teach pendant is pressed.

    • An e-stop button connected to the robot e-stop non-configurable safety input of the control box is pressed.

  • 1: Robot is not in e-stop by robot.
Safeguard stop

  • 0: The robot is stopped due to one of the following conditions:

    • A safety PLC connected via PROFIsafe has asserted the safeguard stop.

    • A unit connected to the safeguard stop nonconfigurable input of the control box has asserted the safeguard stop.

    • A unit connected to the safeguard stop configurable safety input of the control box has asserted the safeguard stop.

  • 1: The robot is not stopped due to a safeguard stop.

Also refer to the “Reset safeguard stop” signal description. PROFIsafe enforces the use of the safeguard reset functionality.
 
Signal Description
Safeguard stop auto

0: The robot is stopped because it is operating in Automatic mode and one of the following conditions applies:

  • A safety PLC connected via PROFIsafe has asserted safeguard stop auto.
  • A unit connected to a safeguard stop auto configurable safety input of the control box has asserted safeguard stop auto.

1: The robot is not stopped due to safeguard stop auto.

Also refer to the “Reset safeguard stop auto” signal description. PROFIsafe enforces the use of the safeguard reset functionality.
3PE stop

  • 0: The robot is stopped because it is operating in Manual mode and one of the following conditions applies:

    • Any 3PE is pressed to the middle position, and Freedrive input is active.

    • Not all 3PE devices are pressed to the middle position.

  • 1: Robot is not stopped because of a 3-position enabling device.
Operational mode

Indication of the active operational mode of the robot.

  • 0: Disabled

  • 1: Automatic

  • 2: Manual
Reduced

  • 0: Reduced safety limits are active.

  • 1: Normal safety limits are active.
Active limit set

The active set of safety limits.

  • 0: Normal

  • 1: Reduced

  • 2: Recovery
Robot moving

  • 0: Robot is moving. If any joint moves at a velocity of 0.02 rad/s or higher, the robot is considered in motion.

  • 1: Robot is at standstill.

Safe home position

  • 0: Robot is at rest (robot not moving), and in the position defined as the Safe Home Position.

  • 1: Robot is not at rest, or not in the position defined as the Safe Home Position.