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 !

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

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....

Ah, so it used to work and now doesn't?

We had a working setup, but the PC had a disk failure and so I had to set up a new one, compiling the module etc. I managed to get everything running again except the speed of the spindle.

I'm fiddling around with this issue for a while and we had backups of the config files and the setup in the VFD, but I have no idea from when these backups are. Unfortunately I can't ask the guy who set up everything (incl. working speed command) up ....

The problem is my limited understanding of the technical background (but I'm willing to learn ) and that I don't really know where the problem lies: in the settings of the VFD, in the config of LinuxCNC or the source of atv_vfd module.

Yes - the developer was so kind and point me to the line in the code, where the frequency is calculated, I changed the relevant factor and now everything is working like expected !

Thanks a lot!