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10.5 Safety Checksum

The text in the top right corner of the screen gives a shorthand representation of the safety conﬁg-

uration currently used by the robot. When the text changes, this indicates that the current safety

conﬁguration has changed as well. Clicking on the checksum displays the details about the cur-

rently active safety conﬁguration.

10.6 Safety Modes

Under normal conditions (i.e. when no protective stop is in effect), the safety system operates in

one of the following safety modes, each with an associated set of safety limits:

Normal mode: The safety mode that is active by default;

Reduced mode: Active when the robot TCP is positioned beyond a Trigger Reduced mode plane (see 10.12),

or when triggered using a conﬁgurable input (see 10.13).

Recovery mode: When the robot arm is in violation of one of the other modes (i.e. Normal or Reduced

mode) and a Stop Category 0 has occurred,

the robot arm will start up in Recovery mode. This

mode allows the robot to move slowly back to the allowed area using MoveTab or Freedrive.

It is not possible to run programs for the robot in this mode.

WARNING:

Note that limits for joint position, TCP position and TCP orientation are

disabled in Recovery mode, so take caution when moving the robot

arm back within the limits.

The subtabs of the Safety Configuration screen enable the user to deﬁne separate sets of safety

limits for Normal and Reduced mode. For the tool and joints, Reduced mode limits regarding speed

and momentum are required to be more restrictive than their Normal mode counterparts.

When a safety limit from the active limit set is violated, the robot arm performs a Stop Category

0. If an active safety limit, such as a joint position limit or a safety boundary, is violated already

when the robot arm is powered on, it starts up in Recovery mode. This makes it possible to move

the robot arm back within the safety limits. While in Recovery mode, the movement of the robot

arm is limited by a ﬁxed limit set that is not customizable by the user. For details about Recovery

mode limits, see the Hardware Installation Manual.

10.7 Freedrive Mode

When in Freedrive mode (see 13.1.5) and the movement of the robot arm comes close to certain limits,

the user will feel a repelling force. This force is generated for limits on the position, orientation and

speed of the robot TCP and the position and speed of the joints.

The purpose of this repelling force is to inform the user that the current position or speed is close

to a limit and to prevent the robot from violating that limit. However, if enough force is applied

According to IEC 60204-1, see Glossary for more details.

Version 3.10

II-7 CB3

Universal Robots UR3/CB3 User Manual

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