Siemens Sinumerik 840D sl Function Manual page 68

Safety Functions integrated in the drive
4.5 Safe Brake Control (SBC)
The Motor Module carries out a check to ensure that the Safe Brake Control func-
tion is working properly and ensures that, if the Control Unit fails or is faulty, the
brake current is interrupted and the brake applied.
The brake diagnosis can only reliably detect a malfunction in either of the switches
(TB+, TB--) when the status changes (when the brake is released or applied).
If the Motor Module or Control Unit detects a fault, the brake current is switched off
and the safe status is reached.
Safe Brake Control for Motor Modules in the chassis format
To be able to control the high rating brakes used with devices of this format, an
additional Safe Brake Adapter (SBA) module is needed. You can find more infor-
mation on the connection and wiring of the Safe Brake Adapter in the Equipment
Manual "SINAMICS G130/G150/S120 Chassis/S120 Cabinet Modules/S150 Safety
Integrated".
Parameters p9621 are used to define which digital input the Safe Brake Adapter's
feedback (brake released or applied) is channeled to the Control Unit or the Motor
Module.
The additional functionality and the control of the brake, in other words, reaching a
safe state, are in this case essentially the same as the sequence for booksize
units.
Response time with the Safe Brake Control function
The following values can be specified for the response times when the function is
selected/deselected via input terminals:
S Typical response time
4x safety monitoring clock cycle CU (r9780) + inputs/outputs, sampling time
(p0799)
S Maximum response time that can occur when a fault develops
8x safety monitoring clock cycle CU (r9780) + inputs/outputs, sampling time
(p0799)
Example:
Assumption
Safety monitoring clock cycle CU (r9780) = 4 ms and
Inputs/outputs sampling time (r0799) = 4 ms
t = 4x r9780 (4 ms) + r0799 (4 ms) = 20 ms
R_type
t = 8x r9780 (4 ms) + r0799 (4 ms) = 36 ms
R_max
Parameter overview (see Chapter 8.2.1 "Overview of parameters")
S p0799
S p9621
S r9780
S p9821
S r9880
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SINUMERIK 840D sl/SINAMICS S120 SINUMERIK Safety Integrated (FBSI sl) - - 10.2015 Edition
CU inputs/outputs sampling time
BI: SI signal source for SBA (Control Unit)
SI monitoring clock cycle (Control Unit)
BI: SI signal source for SBA (Motor Module)
SI monitoring clock cycle (Motor Module)
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