problem in Simoreg 6ra27 spindle drive

[bhowal]

I am using simoreg 6ra27 drive for wheel of roll grinding machine.
I have noted fluctuations in speed and current with load and also in no load condition.
I have changed the tacho belt, the tachogenerator, A1 card as well as A2 card and CTs. I have tried out with a seperate screened cable for tacho also. No improvement has been noticed in any case. I have tried out a different motor. This too has not yielded any result.

The fluctuations minimise if the parameter p31 is reduced from present 15.3 to 2.5.

If anybody has a suggestion please help me.

 

[Prince]

It is just an experience you might find handy. Normally with DCs when I have fluctuation after exhausting work on the poor DC converter and checking everything I find it a sensor problem. I am not sure the type of tacho and the type of tacho belt you are using. I normally work with digital encoders and direct couple. but it is a routine for me if I have fluctuation I will change the speed sensor and the mid devices such as belts or coupls (for encoders it is worth changing we normally have some spares) cause these devices get tired after some monthes of working and unbalance the close loop control.