Basics Regarding The Safety Functions Integrated In The System/Drive; Monitoring Cycle; Crosswise Data Comparison (Cdc) - Siemens SINUMERIK 840D sl Function Manual

Basics regarding the safety functions integrated in the
system/drive
Motion monitoring functions with a higher-level control
The motion monitoring functions are carried out using a higher-level control. The higher-level
control and the drive are the two monitoring channels. Just like the monitoring functions
integrated in the drive, also here, each channel must be assigned a switch-off signal path so
that when a fault develops, the pulses can be cancelled independently of the other channel.
● The switch-off signal path of the Control Unit is assigned to the drive monitoring channel.
● The switch-off signal path of the Motor Module is assigned the control monitoring channel.
6.1

Monitoring cycle

Setting the monitoring clock cycle time
The axis-specific safety-related functions are monitored cyclically in the monitoring clock cycle
that can be set jointly for all axes/spindles using the following machine data:
for 840D sl
MD10090 $MN_SAFETY_SYSCLOCK_TIME_RATIO
The specified clock cycle is checked and rounded-off to the next possible value when the
control boots and every time the machine data changes.
The resulting monitoring clock cycle is displayed using MD10091
$MN_INFO_SAFETY_CYCLE_TIME .
for SINAMICS S 120
p9500 SI Motion monitoring clock cycle (Control Unit)
Monitoring cycle
The monitoring clock cycle determines the response time of the safety-related functions. It
must therefore be selected to be <= 25 ms. The higher the monitoring cycle setting, the greater
the amount by which the monitored limit value is violated in the event of an error and the more
that the drive(s) overshoots.
6.2

Crosswise data comparison (CDC)

The continuous comparison of the safety-related data in the monitoring channels carried out
in the SI monitoring clock cycle is known as "crosswise data comparison" (CDC).
Safety Integrated
Function Manual, 12/2017, 6FC5397-4BP40-6BA1
WARNING
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