PowerFlex 700 Position Indexer

Does anyone have experience using the Position Indexer Feature with a powerflex 700 drive. Below is what we are trying to accomplish.

We have an existing mechanical walking beam system that is driven by a hydraulic motor. Each time the machine cycles the hydraulic motor drives the transfer table through one full rotation (360°). The hydraulic motor and control valve are now obsolete so we ordered the new drive system that the OEM recommends which consists of an Electric AC motor coupled to a gearbox, however the OEM will not include controls, therefore we are doing the controls ourselves.

We are planning to use a powerflex 700 to control the motor with an encoder on the transfer table to measure position. My question is this.

Should I attempt to use the postion indexer function built into the drive or would I be better off doing the control with a ControlLogix with a motion module and the motion instructions built into RSLogix.

Precise position control is not required. I just need a relatively smooth accel and decel and it needs to stop near home position each cycle.

If this walking beam isn't any different than the ones I/we are used to then I wouldn't bother with an encoder. You don't need to know the position of the beam all the way through the cycle, just at a couple of points. Unless you use an absolute encoder you are going to need a limit switch anyway for home position.

I would do this with two limit switches. One for home position and one for a slow down position. At the beginning of the cycle start the drive at full speed, after the pipe is transfered somewhere near the bottom of the cylcle hit the slow down switch, slow the drive down to about 20hz and then wait for the stop switch.

A good way to mount the limits is with adjustable cams on the beam shaft.

The gangsaws down south that we are familiar with had 9 encoders total for them when I got there. What a nightmare. Encoders and hammering walking beams with tons of pipe on them don't last very long. I wriped all of them off and institued a scheme similar to what I just described, never worked better.

OK. Thanks Scott.