Limitations - Siemens SINUMERIK 840D sl Function Manual

05.08
7.4.4

Limitations

During the brake test, traversing to fixed stop and/or traverse with limited torque
FOC may not be active at the same time. In this case, Alarm 20092, "Axis %1
travel to fixed stop still active" is triggered.
The axis should be transferred back from the PLC after the brake test has been
completed.
During the brake test, contour monitoring is not active. After the PLC has started
traversing motion then there is also no standstill monitoring.
The function test/check of the brake mechanical system cannot be used for gantry
axes.
If the parameterization of parameter p1532 (> 5%) deviates from the measured
torque at the start of the brake test – then the brake test must be carried out in the
same direction in which the load torque is effective. In the case of an error – Alarm
20097 "Axis %1 incorrect brake test direction" is output.
7.4.5 Activating
The brake test must always be started when the axis is at a standstill. For the en-
tire duration of the brake test, the enable signals of the parameterized axis must be
set to enable (e.g. the controller inhibit, feed enable signals). The signal "PLC–con-
trolled axis" (DB "Axis".DBX28.7) must still be set to 1 by the user program for the
entire duration of the test. Prior to activating the signal "PLC controlled axis", the
axis must be set as "neutral axis", e.g. set byte 8 in the axis DB to channel 0. Set
the activating signal in the same byte. The block may not be started until the NC
feedback signal has been received via the appropriate bit (DB "Axis".DBX63.1).
For a PLC–monitored axis, also see:
References:
Warning
!
The brake test must be carried out before carrying out the test stop. If the brake
test was not successful (i.e. the brake cannot hold the axis), then it is not
permissible that the test stop is carried out. Users must carefully take this into
consideration when configuring the brake test and test stop. The brake may only
be tested when the axis is in an absolutely safe position.
© Siemens AG 2008 All Rights Reserved
SINUMERIK 840D sl/SINAMICS S120 SINUMERIK Safety Integrated (FBSI sl) – 05.2008 Edition
/FB2/ P2 "Autonomous single–axis processes"
Connecting Sensors/Actuators
7.4 Safe brake test (SBT)
7-259