Sinamics S120 unused drives

Hi,

I think you already did the correct workaround with a simple asynchronous motor without encoder. So the drive will not notice whether there really is a hardware connected or not.

I think your communication error has another reason and is not caused by your hardware configuration of this Double Motor Module. Maybe the PLC startup takes longer than the drive startup and thus the drive is waiting too long for signals from the PLC? 

Cause:
There is no clock synchronization or clock synchronous sign of life and DSC is selected.
Note:
DSC: Dynamic Servo Control
See also: p0922 (IF1 PROFIdrive PZD telegram selection), p1190 (DSC position deviation XERR), p1191 (DSC position controller gain KPC)

Remedy:
Set clock synchronization across the bus configuration and transfer clock synchronous sign-of-life.
See also: r2064 (PB/PN diagnostics clock cycle synchronism)

I did not test that configuration myself but my recommendation is not to use tel 105 for that spare axis. Just do not use any specific telegram or maybe simply tel 1 without IRT communication. Don't forget to re-download the PLC Hardware config after the changes (and of course also download the drive settings again after changing the telegram settings).

For asynchronous motors without encoder you can just do speed control so I would go for a more simple and also non-IRT telegram such as tel 1 when using the TO SpeedAxis (or this would also work without TO, but with SINA_SPEED FB).

Hello,

and p300 = 0 no motor doesn't work?

With regards

Martin