Schneider M221 to atv312 via modbus

Hi
I have an m221 set up with an atv312 and trying to control it over modbus.
No problem with the sample program within so machine basic but now trying to change other parameters. I can't get any other parameters to change from what are set in the atv. Doesn't seem to only be setting up another %write_var with the address ie acceleration ramp 9001 to change the acceleration time and setting a%mw with the required value. Read the sample help pdf but vary vague.
If someone could demonstrate changing a parameter in addition to the sample file then I work out the rest.
Starting to drive me mad so any advice would be appreciated or reference to any example files or good books would be great.

http://www.plctalk.net/qanda/showthread.php?t=99112

The above thread may help you out.

Regards,

Hi Garry
Thank you, I saw that thread before.

I have it working to a degree now. It seems that you need to write each block in sequence one after the other using the " %WRITE_VAR*.DONE " as a trigger for the next else comes back with a comm error.
Probably an easier way so still experimenting.

Thanks

Of course, it is serial data and only one comm can be active one time.
Use counter and count up, when earlier comm is completed (query OK or error)