Speed Change

if I do this speed change, I will like to know that there will be no influences from my motors drives and frequenas inverter, so that all values have time to update.

how do I do this calculation?
i count in all my inputs / outputs / words / bytes wo is being seends to nodes.
and then dividing by the speed of the profibus?

But then i only get how fast the update is on the 1,5mb/s

Any suggestion

reggads
Berra

http://www.google.com/dictionary?source=translation&hl=sv&q=&langpair=

I'm guessing that you would like to increase the speed of your profibus comms.

The ideal speed for profibus is: "as fast as you need it and no faster" Making the profibus run faster will make it more "fragile".

The bus cycle time is calculated by the hardware configuration tool; right click on the profibus object then select properties, Select the Network Settings tab and then press the Bus Parameters button. t_bit is the fundamental timing element of the bus and all other functions are multiples of t_bit. Increasing your bus speed will shorten t_bit. The bus cycle time is expresses as Ttr (Token rotation time) as a multiple of t_bit which is usefully converted to mS.

Increasing the bus speed may influence some control loops on the system but to sure you need to know the update times of your control loops.

Example 1. If a PID loop updates every 20 ms and you bus cylce time is 10ms then increasing the bus speed will give you no advantage.

Example 2. If a PID loop updates every 10 ms and you bus cycle time is 20ms then the bus speed needs to be increased so that the bus cycle time is less than the PID update time so that the same conditions are not processed twice by the PID loop.

Nick

Hrm. the probelem wi have now is: When we are connecting one more simoCode to the spureLine we get bus error, the error disipird when we change the Bus Speed, But i'am afriad that the bus speed is to slow, and how do a calculate that??

Changing Bus speed from 1,5mb/s to 500 kb/s

If my memory serves me right, simocode does not autoselect its speed. So what bus speed is configured in simocode?

Ok, so in under words that should not be a problem to slow than, the speed on the bus, if i change the bus speed on the Simocode

Generally speaking, Spurs on profibus should be avoided as they cause reflections which will limit the speed of the bus.

The bus cycle time is calculated by the hardware configuration tool; right click on the profibus object then select properties, Select the Network Settings tab and then press the Bus Parameters button. t_bit is the fundamental timing element of the bus and all other functions are multiples of t_bit. Increasing your bus speed will shorten t_bit. The bus cycle time is expresses as Ttr (Token rotation time) as a multiple of t_bit which is usefully converted to mS.

Click to expand...

See attached picture.


Nick

Ok,thanks