Re: [CAD_CAM_EDM_DRO] Pulsing circut

David,
if position is always the same you can lock in a place by mechanical means.
Alex

David Paulson wrote:

>Hi
>I am in the process of constructing a rotary table for use with my
>welding robot. I have a large (36" dia) cnc rotary table that I had
>purchased on ebay. It has a 140v DC servo mounted on it for the
>movement. I have purchased a AMC brush type dc servo amp that has a
>step (com, +10v) and direction (com, +10v) pins. My idea was to
>program a plc with the required foot switch and two limit switches (one
>for each position of the table) to control the servo amp and communicate
>with the robot controller. I chose to power the servo though the servo
>amp because when power is removed from the step pin, the motor will stop
>instantly, but the problem is the speed at which the table turns. The
>limit switches do not accurately activate at the same place each time.
>So my next idea is to install another set of limit switches approx. 1
>1/2" before the position limit switch and to send a pulsing circuit to
>the servo amp to effectively slowing down the motor so that the position
>limit switch can more accurately sensed. Does this make sense to
>anyone? So my question is, does anyone know how to build such a
>circuit, possibly using a pot to adjust the frequency of a +10v pulse.
>Thanks
>
>David Paulson
>
>
>
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