10
Response times
Calculation of response times
Manual – MOVISAFE
®
CSB51A Safety Option
36
10
Response times
The response time plays a decisive role in the design and execution of drive safety
functions in systems and machines. In order to match the response time to the re-
quirements of a drive safety function, always take the entire system into account, from
the sensor (or command device) to the actuator. The following times are of particular
importance in connection with the MOVISAFE
®
CSB51A safety option:
•
Response time of the connected sensors
•
PROFIsafe cycle time
•
Processing time (cycle time) in the safety controller
•
PROFIsafe monitoring time
F_WD_Time
•
Internal response times of the MOVISAFE
®
CSB51A safety option
•
Response time of the actuators (e.g. frequency inverters)
Establish the response sequence for each drive safety function in your application and
determine the maximum response time for each case, taking into account the relevant
manufacturer data. Observe in particular the information contained in the safety docu-
mentation of the safety controller used.
For detailed information regarding response time consideration for safe PROFIsafe
communication, refer to the respective standard: IEC 61784-3-3.
10.1
Calculation of response times
The following response times are fixed:
•
T
_Sys
= 4 ms (cycle time of the system)
•
T
_Task
= 0.5 ms (cycle time of a process)
•
Maximum fault response time T
_FRZ
= 9 ms applies to the deactivation of the in-
ternal output F-DO_STO and to setting the fault status of the safe process input
data (F-PE).
10.1.1
Safe communication
All response times must be multiplied by the factor 1.002.
Calculation factor (formula symbol)
Calculation specification response time
Input processing time via safe process out-
put data
(T
_InputProcessing_F-PA
)
2 × T
_Task
+ T
_Sys
Response time (F-PA after F-DO_STO)
T
_InputProcessing_F-PA
+ T
Sys
10.1.2
Selection of a drive safety function via safe communication
The response times for the safe communication always relate to the safe protocol and
not to the external interface of the safety option. All response times must be multiplied
by the factor 1.002.
Calculation factor
Calculation specification response time
STO:
•
Via F-PA
T
_InputProcessing_F-PA
+ 2 × T
_Sys
25931075/EN – 04/2019
