Traversing Direction For The Brake Test; Brake Control For Sinumerik 840D Sl - Siemens Sinumerik 840D sl Function Manual

Connecting Sensors/Actuators
7.6 Safe Brake Test (SBT)
7.6.4

Traversing direction for the brake test

The brake test must always be started when the axis is at a standstill. The direc-
tion in which the drive produces its force is specified by the PLC using the direction
specified by the traversing motion of FC18. For a brake test, the motor should
apply a force to the brake that is applied in addition to the force due to weight. The
target of this traversing motion must be able to be reached without incurring any
potential hazard (sufficient clearance to end stops) for the case that the brake can-
not provide the necessary force. As part of the application, the position can be
interrogated using conventional cams (not safety cams, as this is not a safety--
related function) that then define the traversing direction of the axis via FC8 during
the braking test.
If a brake test is executed against the force due to weight, in spite of the closed
brake, the motor must generate a torque corresponding to the force due to weight
and the test torque.
Note when using MD36968 $MA_SAFE_BRAKETEST_CONTROL, bit 0 = 0:
If a traversing direction is selected that opposes the force due to the weight, Alarm
"20097 axis %1 incorrect direction braking test" is initiated, if the actual torque,
when selecting the brake test deviates by more than 7.5% of MD36966
$$MA_SAFE_BRAKETEST_TORQUE from drive parameter p1532. This alarm
indicates that the brake test was executed with a torque that was incorrect by more
than 15%. Principally, the automatic determination of the available load torque
using MD 36968 $MA_SAFE_BRAKETEST_CONTROL, Bit 0 = 1 is the preferred
solution (see Chapter 7.6.2, Section MD36968 $MA_SAFE_BRAKETEST_CON-
TROL: Sequence control for the brake test).
7.6.5

Brake control for SINUMERIK 840D sl

If Safety Integrated is activated for an axis, then the brake can be closed using the
interface signal "Close brake", DB31--61, DBX23.5. The feedback signal is realized
using the interface bit "Motor holding brake open", DB31--61, DBX92.5. This in-
volves a single--channel control configuration. If the brake is to be safely controlled,
then the SBC function integrated in the drive must also be activated. The interface
bits for the brake, only activated in conjunction with Safety Integrated, have a
higher priority than the standard interface signal DB31--61, DBX20.5 "Open motor
holding brake". The "Extended brake control" function of the S120 is used inde-
pendently of SBT.
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SINUMERIK 840D sl/SINAMICS S120 SINUMERIK Safety Integrated (FBSI sl) - - 10.2015 Edition
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