Problem with Flexmotion 7344, UMI 7764 and servo driver parts

[Andrea S.]

Hi to all of you, I've a great problem with my motion system.
This is formed by:
1.Flexmotion 7344, cable and UMI 7764 (NI-kit)
2. 2 servomotor and 2 incremental encoder
3. 2 Motor drivers

The problem is that the motor drivers (AXOR MICROSPEED) can' t work with the NI-kit, sometimes the motor go and sometimes not, so the repeatabitlity is very very low.
I work a lot trying to solve this but i suppose that the PID of the driver runs counter to the PID of the Flexmotion.
This thing was confirmed by the NI Italy staff. They tested the system and comfirmed my sensations but i had not any feedback about the type of drivers that i' ve to buy to work with my system.

I try to attach the datasheet of the motors and the encoders at the post.
If any one can help me in some ways i thank a lot. If necessary is possible to contact me by mail at a.sassaroli@univpm.it

Motor type: 17PL085
Encoder type: EH17 M500 Z 5 P 6 X 3 P R 7 8

The last important thing is that the system with this configuration of motors, encoders and drivers worked in the past with the old NI flexmotion 6C.
What we would do is to mantain this configuration of motors, encoders and drivers but substitute the old flexmotion with the new.

Thanks to all.
Andrea

[Brian_Beal]

Do you have the torque mode option for the Axor drive?  That is really what you need.

[Andrea S.]

Hi Brian. Thank you for the reply.
When you talk of "torque mode" you mean the possibility of using the drive as a current amplifier?

Thanks
Andrea

[Brian_Beal]

Andrea-

Yes.  According to the datasheet, that drive can be ordered in different versions.  There are different options like control mode and feedback type.  Please give us your part number.  Typically, position controllers expect the drive to accept a torque reference(+/10V).  It is possible to use it in velocity  mode, but you need the differential option.  If that is the case, then you have 2 PID loops to worry about and tune.  One in the drive, and one in the controller.

Brian