Speedcommand Modbus driver for An Altivar ATV71 VFD

We are using the following module for controlling our VFD:

wiki.linuxcnc.org/cgi-bin/wiki.pl?Contri...ATV71_VFD_driver_atv

The link to the git is down, but it's available on another forum:

www.c-n-c.cz/viewtopic.php?f=34&t=4869

The problem is, that the start/stop command works, but the speed command doesn't (We had this working, so I know it's possible). I found out, that there are two different addresses for these two commands, but I don't know where to set it. I searched the settings of the VFD, but I could not find this parameter.

Any help appreciated - Thanks !

Have you looked at the component code?

Yes - in the xls file with the atv parameters I can find:

CMD 16#2199 = 8601 (speed)
16#2135 = 8501 (frequency)

....and in the code I can find:

#define REG_CMD 0x2135 // Control Word CMD 8501 frequency


So I would say it's correct ....... but it's not working....


Do I have to set the address in the atv or is it fixed??

I analyzed the problem further and I found out, that the atv_vfd module IS sending out a speed command. Unfortunately it's not the right one. If I send out 6000rpm (which is 100Hz at the ATV and the lowest speed of our spindle) the ATV runs at 12,5Hz, with 9000rpm 18,7Hz etc.

I really have run out of ideas where the problem is. Maybe someone can point me in the right direction!

Thanks a lot in advance!

Easy answer: Just send 8x the speed you really want

It is hard to see what might be doing this at the VFD end. An easy explanation for the inverse problem would be that the motor poles setting is wrong, but it seems unlikely that it could be configured to be a 0.25 pole motor...

So, just fudge things in the code that you do have access to.

Easy answer: Just send 8x the speed you really want

Well - I had this idea already .... We had it working, that's why I actually don't want to fudge it.... but maybe that's the "easiest" solution....