Product description
108928_en_02
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3.9
Safety-related system time
3.9.1
Processing time of the input in the event of a safety demand
The processing time of input t
IN
in the event of a safety demand consists of parameterized
filter time t
Filter
and the firmware processing time t
FW
.
Key:
3.9.2
Error detection time
If a “1” signal is present at the input and an error occurs, a maximum of 64 ms elapses until
the error is detected.
During this time, another “1” can be transmitted, even in the event of an error.
3.9.3
Duration of a safety demand
The duration of a safety demand must be greater than the processing time of the corre
-
sponding input t
IN
.
If the Smart Element detects a safety demand after the processing time of input t
IN
has
elapsed, the Smart Element extends the demand until the controller has received the
demand.
t
IN
= t
Filter
+ t
FW
t
IN
Processing time of the input
t
Filter
Parameterized filter time
t
FW
Firmware processing time: 7,5 ms
WARNING: Unexpected machine startup
During the error detection time, the error can cause the state to change unexpectedly from
“0” to “1”.
•
Make sure that the system cannot be restarted unintentionally as a result of this
change in state.
NOTE: Extending the processing time in the event of an error during 1-channel
operation
During 1-channel operation, the error detection time affects the processing time of the
input.
•
Observe the error detection time during 1-channel operation.
WARNING: Loss of the safety function
If the duration of the safety demand is too short, this can result in the loss of the safety func
-
tion.