Siemens SINUMERIK 840D sl Function Manual page 251

05.08
$MA_FIXED_STOP_MODE
The function test of the mechanical braking system is enabled by setting bit 1 in
$MA_FIXED_STOP_MODE. If the user needs to travel to a fixed stop with this
axis from the part program, bit 0 can also be set. It is internally monitored to check
that only one type of travel to fixed stop is active at a time. In the case of an error,
Alarm 20092, "Axis % Travel to fixed stop still active" is issued.
$MA_SAFE_BRAKETEST_TORQUE
The machine manufacturer must parameterize the total required brake holding
torque in the axial MD $MA_SAFE_BRAKETEST_TORQUE. Internally, this is used
to calculate the drive torque that is required in addition to the weight of the axis to
load the brake.
For SINAMICS S120 the drive torque is determined when the function test is se-
lected. It is thus possible to take into account any deviation from the torque due to
weight parameterized in drive parameter p1532 (or force due to weight). This en-
sures that the brake test can also be carried out with varying machine loads (e.g.
different workpieces or tools). The drive torque to load the holding brake is limited
to the maximum motor torque if the desired braking torque would require a higher
drive torque.
If the load torque at an axis changes so significantly that a sensible value cannot be
parameterized in drive parameter p1532, then the automatic determination of the load
torque available must be activated using $MA_SAFE_BRAKETEST_CONTROL.
Value for MD36966 = (test torque of brake / p2003) * 100
The value from $MA_SAFE_BRAKETEST_TORQUE refers to the reference
torque or the reference force from drive parameter p2003, whose image is saved in
$MA_SAFE_BRAKETEST_TORQUE_NORM.
© Siemens AG 2008 All Rights Reserved
SINUMERIK 840D sl/SINAMICS S120 SINUMERIK Safety Integrated (FBSI sl) – 05.2008 Edition
Connecting Sensors/Actuators
7.4 Safe brake test (SBT)
7-251