Hello Jonas;
I would like to comunicate with PPO1 (4 words for PKW, 2 for PZD).
For the 2 PZD (process data), meaning the control word and the speed setpoint you do not (can not, must not) use SFC14/15. Since each PZD word is complete by itself, you just MOVE (Load/Transfer) the correct value to the required address:
Speed Setpoint: a hex value of 4000 (100% max. parametered speed) moved to PQW258 (since the base address is 256)
Control word: a hex value of 047E, then 047F to PQW256 to start the motor and ramp up to the speed setpoint selected. Then write 447F to the same address for a rotation change, 447E or 047E to stop the drive, etc... The MM420 manual will show you the bit per bit definition of the control word.
For the PKW (parameter words), you must send the 4 words as one unit (consistency total)top the drive; this means 8 bytes of data at one shot, more than the 4 byte limitation you mention. This is where you need SFC15. You must setup a DB or M zone with 4 words containing the adequate data to read/write specific parameter information: check the MM420 manuals to check out the details. Just as an example, setting up 4 contiguous words with the following hex values:
2002 // first nibble indicates read(1) or write(2);
//lowest nibbles: parameter number
0000 // not used for this parameter but must be present
0000 // not used for this parameter but must be present
000A // a value of 10 is written to the parameter selected
and sending them to PQW260 top PQW267 through SFC15 will write 10 seconds to the acceleratrion ramptime parameter (No. 2).
Hope this helps,
Daniel Chartier
