This is the scenario: Lets say we have a catenary arm with a pot on it that monitors the catenary position. This arm has a chive (roller) where we wrap wire around it to serve as a pully. As the wire starts to be pulled away from the machine, this arm will move thus moving the POT which signals the drive to give the reel of wire a push to maintain the catenary arm in a desired position.
Now, we use regen drives for this application (Penta KB series) to be exact, and here is the problem.. The load on the shaft is heavy and what happens is when the catenary arm moves in position to signal the drive, there may be a delay of response due to the extra swing load of weight and thus the arm might end up in a position where high bias voltage is now at its point and when the shaft finally gets going in the other direction, it goes to fast! And thus, this extra weight generates a lot of it's own momentum. (Swing load).
This is what i want to know before i go and build it. cause if it's on the market i would rather buy it.
I need to detect the speed of which the catenary arm is moving, not the reel speed! I do not want to employ encoders on the shaft because of expense reasons. It must generate a negative response to what the POT wants the drive to do as the POT starts to change position and as soon as the pot stops, the POT's real signal will be reported at the position it is currently in. I need this type of control to not allow the drive to accelerate so fast that the catenary arm whiplashes. My thoughts on this for ideal thinking, is something like a voltage follower that mirrors the POT's signal, a capacitive system will create an inhibiting signal as the voltage changes but not inhibit when the voltage from the POT is stable or changing very slowly.
The end results is, the POT's signal to the drive will change slowly to get the catenary arm into position but not too slow where it will cause it to stall in position. Lead, Lags, Delays etc found on most Dancer and drive controls does not do what i need, due to the fact that a lot of these circuits tend to memorize last time effects and just compound the problem.
I hope i have made this clear enough, if there something on the market in like a mini board form that runs off lets say the REF's supply voltage of around 10 or 15 volts that conditions the signal it would be nice.. Other wise, i will have to make my own debouncer circuit..
P.S. we have already tried outboard dancer boards like the old Reflex series and the drive it self has an extensive set of controls which serve their purpose just fine how ever, none of them give me this kind of control.
I have seen this in eurotherm digital drives where the max speed can be retarded by the rate in which the POT value changes. The faster the POT changes, the slower the drive/motor attempts to go. but in our case, we are using non-digital drives ( a lot of them) with Armature feed back!.. Thanks for any input.