Siemens V90 encoder monitoring faults

Dear Siemens Experts,

I managed to get the Siemens S7-1500 and V90 configuration working properly.
The servo motor in question is the 1FL6062-1AC61-0AB1
Every light is green and there are no errors given by the program.

In the 'Commissioning' tab I opened the axis control panel.
This is where the problems start. I can't get a proper motor axis control and the encoder feedback to the plc seems far from correct. 
The motor moves randomly (gives a high frequency tone while an input is given), but it does not always move. A couple seconds later it stops with the error "posititon monitoring error" (error in the V90 drive is '5  OFF').
Also the velocity and posititon in the current values does absolutely nothing, sometimes the position is a random number.
Sometimes the servo motor jitters for 300ms while powering on for the first time.

For so far I know I entered the correct values in the program.
- 2000RPM in the tab "data exchange with the drive".
- Incremental encoder in the tab "Encoder"
- 13 bits Gx_XIST1 and 2500Increments per revolution in the tab "data exchange with encoder"(changing the bits from 0-30 doesn't change anything on the functionality).
- The drive is assigned properly in the hardware interfaces
- Standard telegram 3 is used in the encoder and drive telegram

One other thing I noticed is:
In the Axis control panel, rotating the motor backwards does not work, looks like it moves and then directly brakes again? The motor only shows action when moving forward.

I tried everything to get something close to a real measured/controlled action out of the system, but there has not been any yet.

Does anybody has an idea?
I would highly appreciate it.
Thanks in advance.

Kind regards,
MVG

Hi sir,

Thanks for your reply!
You were right, in V-assist the motor was not configurated correctly.
The motor runs smooth currently and it made it's first good rotations.
Thanks!