Response times 
 
ET 200S Distributed I/O System - Fail-Safe Modules 
Installation and Operating Manual, 08/2008, A5E00103686-07 
203 
 
Note 
Please note that the Excel files for calculating the maximum response times (
s7fcotia.xls
and 
s7ftimea.xls
) included with the 
S7 Distributed Safety
 and 
S7 F/FH Systems
 option packages 
already support calculation of the extension of the "Maximum response time in the event of a 
fault" by the programmed discrepancy time. 
 
Maximum response time of the EM 4 F-DI/3 F-DO DC24V PROFIsafe 
Formula for calculating the maximum response time if there is no fault: 
maximum response time  
without a fault = T
max
 + input delay + short-circuit test time* 
*: Short-circuit test time = 2 x input delay 
Parameters for the input delay and the short-circuit test are assigned in 
STEP 7
. 
Table D- 7  EM 4 F-DI/3 F-DO DC24V PROFIsafe: Internal Processing Times 
Evaluation of the Sensors  minimum internal processing 
time T
min
 
maximum internal 
processing time T
max
 
1oo2  4 ms  9 ms 
Maximum response time if a fault occurs:  
The table below contains the maximum response times of the F-DI/F-DO module when a 
fault occurs, depending on the parameter settings in 
STEP 7
 and on the sensor evaluation. 
Table D- 8  EM 4 F-DI/3 F-DO DC24V PROFIsafe: Maximum Response Time if a Fault Occurs 
1oo2 evaluation* 
Input Delay  3 ms 
Short-circuit test deactivated  14 ms 
Short-circuit test activated  22 ms 
*: The response times with 1oo2 evaluation also depend on the configured discrepancy behavior: 
Provide 0 value: The times defined in the table above apply. 
Provide last valid value: The times in the table above are extended by the programmed discrepancy 
time.  
 
 
 
Note 
Please note that the Excel files for calculating the maximum response times (
s7fcotia.xls
and 
s7ftimea.xls
) included with the 
S7 Distributed Safety
 and 
S7 F/FH Systems
 option packages 
already support calculation of the extension of the "Maximum response time in the event of a 
fault" by the programmed discrepancy time.