We have a Bulletin 1388b-AV20 servo controller working in conjunction with a TI 500-5024 servo axis controller with a servo motor hooked up. This is a common setup in our facility although we are working on upgrading and replacing with new equipment eventually need to keep these running till that day comes. So we are bench testing and familiarizing ourselves with setting them up and testing ones on the shelves using a VPU unit. The problem we are having is that we apply power to the 1388 controller and get no faults so we then use a switch to jumper the enable command on the 1388 and get our enable light and pull in the contactor in the controller, but with no voltage on the velocity command wires from the TI controller to signal the motor to run, the motor starts to hunt and just keeps rotating slowly... We read that you can eliminate this premature rotation by turning the offset pot ccw and this does work. The problem is though when we run our velocity loop test using the VPU and we need to adjust our tach scale and our offset to get both direction speeds as close to 100 percent as possible we have to turn the offset pot cw quite a ways to get the numbers to even out... Wondering how we get rid of the hunting rotation as soon as we enable without having our velocity loop test numbers 94 and 100, is there a way to solve both problems or will we have to live with one problem or the other? Any advise or input greatly appreciated, thanks!
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