Siemens SINUMERIK 840D Description Of Functions page 125

11.03
3.8 Safe braking ramp (SBR) (840D from SW 4.2)
Fig. 3-24
Calculating the SBR The following applies when parameterizing the SBR tolerance:
tolerance of the actual
The possible speed increase after triggering STOP B/C is made up of the active
speed
acceleration a and the duration of the acceleration phase. The duration of the
acceleration phase is one monitoring clock cycle ÜT (delay in detecting a
STOP B/C until n
SBR tolerance
Actual speed for SBR = acceleration * acceleration duration
The following setting rules apply:
For a linear axis:
SBR tolerance [mm/min] = a [m/s
For a rotary axis/spindle:
SBR tolerance [rev./min] = a [rev./s
To determine the value, the maximum value of the acceleration values should
be taken account from the following list that is also effective for the particular
axis:
MD 32300: MAX_AX_ACCEL
MD 35200: GEAR_STEP_SPEEDCTRL_ACCEL
MD 35210: GEAR_STEP_POSCTRL_ACCEL
MD 35410: SPIND_OSCILL_ACCEL
Recommendation:
The value entered for the SBR tolerance should be approx. 20 % greater than
the calculated value.
!
© Siemens AG 2003 All Rights Reserved
SINUMERIK 840D/SIMODRIVE 611 digital SINUMERIK Safety Integrated (FBSI) - Edition 11.03
n
Speed
tolerance
n
ist
n
x
Characteristics of the stopping limit value for SBR
= 0):
set
Caution
During "normal" operation, speed overshoot should not unintentionally trigger
the SBR. Speed overshoot should therefore be checked by making the
appropriate measurements.
3 Safety-Related Functions
Stopping limit value
STOP B/C triggered
2
] * ÜT [s] * 1000 [mm/m] * 60 [s/min]
2
] * ÜT [s] * 60 [s/min]
t
SBR_01.DSF
3-125