Response Time - Siemens SIMATIC S7-400H System Manual

19.5

Response time

Definition of response time
The response time is the time from detecting an input signal to changing the output signal
associated with it.
Fluctuation range
The actual response time lies between the shortest and the longest response time. You must
always assume the longest response time when configuring your system.
The section below deals with the shortest and longest response times, in order to provide an
overview of the fluctuation in the length of response times.
Factors
The response time depends on the cycle time and the following factors:
● Delay of the inputs and outputs
● Additional DP cycle times on the PROFIBUS DP network
● Execution in the user program
Delay of the I/Os
Make allowances for the following module-specific delay times:
● For digital inputs: the input delay time
● For digital inputs with interrupt function: the input delay time + internal preparation time
● For digital outputs: negligible delay times
● For relay outputs: typical delay times of 10 ms to 20 ms.
● For analog inputs: cycle time for analog input
● For analog outputs: response time at analog outputs
For information on delay times, refer to the technical specifications of the signal modules.
S7-400H
System Manual, 03/2012, A5E00267695-11
The delay of relay outputs also depends on
the temperature and voltage.
S7-400 cycle and response times
19.5 Response time
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