Siemens SIMATIC ET 200SP - Page 41

Supplements to ET 200SP documentation
2.4 Interface module manuals
Product information on the documentation of the ET 200SP distributed I/O system
Product Information, 02/2021, A5E03799595-BG
41
Table 2- 2 Example calculation
Configured update time
Backplane bus cycle time (integer multiple, minimum 1 ms)
250 µs
4 x 250 μs = 1000 μs
750 μs
2 x 750 μs = 1500 μs
1000 μs
1000 μs
2000 μs
2000 μs
Operating system processing time
The operating system processing time is calculated based on the following formula:
Operating system processing time output
Operating system processing time_output[μs] = 147 + 3.775 number_m + 0.275 bytes_out
Operating system processing time input
Operating system processing time_input[μs] = 158.3 + 2.325 number_m + 0.325 bytes_in
Explanation of the parameters:
Number_m: Total number of all modules (incl. server module)
Bytes_out: Sum of all output bytes
Bytes_in: Sum of all input bytes
Calculating the response time
Response time output
The response time output of the IM 155-6 PN ST is made up of:
• Backplane bus cycle time
• Operating system processing time_output.
Response time input
The response time input of the IM 155-6 PN ST is made up of:
• Backplane bus cycle time
• Operating system processing time_input.