I have an RMC70 with SSI position feedback and pressure transducers for force feedback. I make a move to a position when I get into position I tell it to hold current position and current force. I do this because I see the part expand after it is pressed and I want the axis to move back off position if the force comes up. What I am seeing is the axis get into position and when it gets the hold position/pressure command it moves down increaseing the force. When it is getting into position I see the drive at 2-3% after the command it goes to 50% or higher. This is not a big problem till they want to hold the position/force for a few seconds. In a few seconds the force jumps 25% or better.
My first thought was force tuning. Now I am wondering if the pressure transducers could be backwards. Because it seems like the drive is going backwards. This is a common in position loops thats why you have the reverse drive setting. If the pressure transducers were backwards cap to rod and rod to cap would it give me this type of problem?
I will try to get some plots tomorrow showing what I see.