Safety engineering
Safety functions
Safe PROFIsafe connection
1
1.3
1.3.5
1.3-11
EDS94AYAD EN 2.2
Response time to an event in the safety sensors (PROFIsafe input data)
Time interval (Fig. 1.3-1) [ms]
t
1
Response time of the sensors according to manufacturer
information
t
2
Input delay of the safe inputs
passive sensors: 4+15
active sensors: 0+15
t
3
Processing time in drive-based safety 24
PROFIsafe input data ready for transmission to ... Σ
t
Ps
PROFIsafe cycle time according to manufacturer
information
PROFIsafe input data ready f or processing in the safety PLC
...
Σ
Tab.1.3-4 Responsetimetoaneventinthesensors
Response time to a PROFIsafe control word (PROFIsafe output data)
Time interval (Fig. 1.3-1) [ms]
t
4
Processing time in the safety PLC must be calculated
t
Ps
PROFIsafe cycle time according to manufacturer
information
t
5
Processing time in drive-based safety 14
Safety function starts after ... Σ
Tab.1.3-5 ResponsetimeincaseofPROFIsaferequest
Information on how to calculate the processing time and transmission time
of the PROFIsafe can be found in the documentation of the safety PLC used.
Note!
When the PROFIsafe communication is disturbed, it is changed
to the fail-safe state after the PROFIsafe monitoring time
(F_WD_Time) has elapsed. ( Tab. 1.3-16)
ƒ After an event has occurred at a safe input, the message is fed back to
drive-based safety via the safety PLC.
ƒ Drive-based safety activates a safety function.
ƒ Hence, the maximum response time to the event is calculated as
follows:
t
max response
=t
1
+t
2
+t
3
+max{t
WD
;t
PS
+t
4
+t
Ps
+t
5
}
When calculating the maximum response time, include the times of the
safety functions, e.g. in case of SS1 the stopping time (30 s) until STO is
active.
Example
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