Lenze Drive Server Bus server S7 getting started - Manual (Page 37)

Busserver S7
L
98 Busserver S7 DE/EN 1.0
6 Appendix
6.1 Time load of the PLC cycle
The function blocks are cyclically called. The PLC cycle is permanently under load.
• The exact processing time depends on the computing power of the CPU.
• If real communication takes place, processing takes longer than if a block is activated without a
command to be processed.
• When the PLC program is complete, the cycle load can be reduced by activating the expert
mode. ( ^ 96)
The below table lists typical processing times for two different CPU types:
Block number Processing time
Operation CPU 412-2 DP (S7-400) CPU 315-2 DP (S7-300)
FC90 < 0.1 ms 0.6 ms
FC91 < 0.1 ms 0.7 ms
FC92 < 0.1 ms 0.6 ms
FB90 < 1 ms 1 ... 7 ms
Expert mode < 1 ms 1 ... 3 ms
Idle running < 1 ms 1 ... 2 ms
FB91 1 ... 7 ms
Eypert mode 1 ... 3 ms
Idle running 1 ... 2 ms
6.2 Transfer times
The following characteristics are important for the transfer times.
Tip!
Please note that the times indicated are minimum values.
• If PROFIBUS is under high load or if a complex program is to be processed, times will rise
accordingly and may be considerably longer.
• Communication disturbances and access to PROFIBUS devices that are not available may
substantially affect transfer times.
• Transfer times also depend on the operating system used. For optimum transfer times, we
recommend to use Windows NT, Windows 2000 or Windows XP.
Show/Hide Bookmarks