SIPART PS2 i/p 6DR5020 Failure

Good day,

We are experiencing problems with a PS2 6dr5020. We were able to get it to initialize and once we go into auto it either goes fully closed or fully open. No actuation in between. We have used a signal generator and found that at 4 mA it will close but anything over 4.0039 mA it goes to 100% open. Any thoughts on how to fix this? We used the same settings as the old actuator taken out.

Thanks!

Pat