[quote user="peters"]what will be led to be if the transmission rate of DP (show in the document) be changed higher or lower?

Hi Peters,

It totally depends on what J_Bell also said, how many slaves are on the bus and how many data is transfered between the slave and the master.

Normally when the Baudrate is placed from 1,5 to 12MBit/s a factor 4 til 6 what the reactiontime is faster. But it also depends on the cycletime of the CPU if it brings something. When the walkaroundtime of the Profibus is 3 times as fast as the cycletime then normally you couldn't get your IO faster.

If you want to know how long the terget rotation time is you could look on the time thats in STEP7 behind the Profibus. The time thats calculated there is from the GSD-files and when measured on the bus, the time is less, this because in the GSD-file the time is the worst-case time.

Also the slave with the worst-time (normally the cheaper slaves) is leading for the hole Profibus!!

With ProfiNet you can choose for each device the time you want, so there it is possible to call the devices as fast as you want if the device could manage that.