10.6 Safety Modes
10.4 Tolerances
The Robot Arm uses built-in tolerances that prevent safety violations. A safety tolerance is the
difference between a safety limit and a maximum operational value. For example, the general
speed tolerance is −150mm/s. This means that if the user configures a 250mm/s speed limit,
then the maximum operational speed will be 250 − 150 = 100mm/s. Safety tolerances prevent
safety violations while allowing for fluctuations in program behavior. For example, when han-
dling a heavy payload, there may be situations where the Robot Arm needs to briefly operate
above the normal maximum operational speed to follow a programmed trajectory. An example
of such a situation is shown in figure 10.1.
WARNING:
A risk assessment is always required using the limit values with-
out tolerances.
WARNING:
Tolerances are specific to the version of the software. Updating the
software may change the tolerances. Consult the release notes for
changes between versions.
Time
Speed
Actual speed
Safety speed limit
Maximum operational speed
Figure 10.1: Safety tolerance example.
10.5 Safety Checksum
The text in the top right corner of the screen gives a shorthand representation of the safety
configuration 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 currently 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).
e-Series II-6 Version 3.11
Copyright © 2009–2019 by Universal Robots A/S. All rights reserved.
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