Function description
System Description Service Robotics Modules
1004870-EN-05
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4.8
Brake test function
The aim of the brake test is to check the effectiveness of the holding brakes on the robot
arm. The safety function "Safe retention with holding brakes" is guaranteed while the brake
test delivers a positive result; i.e. following the controlled stop of the robot arm drives (SS1),
no hazard can arise due to suspended loads sagging.
General operating principle of brake test
The motion controller receives the prompt to trigger the brake test from the safety control
system. As soon as the motion controller receives the prompt for a brake test from the
safety control system, the motion controller's robot program can evaluate the prompt; i.e. at
an appropriate time the motion controller's robot program can trigger the brake test on the
robot arm using the "BRAKETEST" command.
If applicable: External
prompt to perform brake
test
Safety control system
with user program
Motion controller with
user program
Robot arm
Prompt to perform
brake test
Trigger brake test
(CAN1)
Feedback from
brake test
Feedback from brake
test (CAN1)
Fig.: Cooperation between safety control system, motion controller and robot arm during brake test (principle)
The programmer is tasked with implementing the specified requirements and procedures
for a brake test within the robot program. The teach pendant contains a service program as
the default robot program for this purpose. The service program can be adapted depending
on the application (see
Default robot program for brake test [
A monitoring time of 9 hours is pre-configured in the safety control system for the duration
between two successful brake tests. The safety control system monitors that the period
between two successful brake tests does not exceed the monitoring time of 9 hours. This
type of monitoring is called a cyclical brake test. Monitoring of the cyclical brake test is al-
ways active, as is monitoring of the brake test after a cold start.
After each successful brake test the monitoring time is reset. The reset occurs irrespective
of how the brake test was triggered.
If the brake test is not performed within the monitoring time or the brake test is performed
but fails, the safety control system triggers the stop function SS1. The robot arm drives will
come to a controlled stop.
Note the information under
Robot movement with time-limited motion enable [
.
