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<blockquote data-quote="Jeff Stevens" data-source="post: 43352" data-attributes="member: 236">Re: Help needed- rotating drum riserI would highly recommend dropping the idea of using DMX.&nbsp; Aside from the fact that it is a one-way protocol, it is built with &quot;best-effort&quot; hardware that often does not contain fault checking measures and a dimmer pack will not be happy driving a motor.&nbsp; Single phase AC motors cannot be reversed unless they contain a second winding, so that that limits you to three phase or DC.&nbsp; Personally, I think a DC motor with a drive would work well in this application.As far as control, a PLC can be found cheaply on eBay and other places.&nbsp; Some of them are even life-safety certified with fault-checking hardware and can be made to do just about anything from running assembly lines at Ford to amusement park rides at Disneyland.&nbsp; Many have integration with motor drives since the same companies tend to make both.&nbsp; The two ways that are standard for this type of mechanism are an encoder and limit switch.&nbsp; A encoder counts the rotations from the motor and using a formula in the PLC, it can figure out where you are and how fast you are rotating.&nbsp; Then it can modify the speed and direction of the drive to put you in the &quot;correct&quot; position in real-time.&nbsp; A limit switch at the end of travel (or at a predefined location mark if it is a continuously rotating system) allows the PLC to correct accumulated errors in its counts.To interlock the system, there should be an E-Stop on both the platform and the ground and a main keyswitch you can use to lock the system when you are away.&nbsp; I would also probably have a pressure switch wired into the seat of a mat underneath you so if you should move out of the &quot;safe&quot; zone then it will stop.&nbsp; To control it you could use a HMI (touchpanel), push buttons, Ethernet, serial, etc. depending on the PLC.&nbsp; There&#039;s all sorts of used industrial automation equipment on eBay these days.&nbsp; A great resource I have used for these questions is <a href="http://www.mrplc.com" target="_blank">Mr. PLC</a>.&nbsp; Sounds like it could be a really cool project.</blockquote>

[QUOTE="Jeff Stevens, post: 43352, member: 236"] Re: Help needed- rotating drum riser I would highly recommend dropping the idea of using DMX. Aside from the fact that it is a one-way protocol, it is built with "best-effort" hardware that often does not contain fault checking measures and a dimmer pack will not be happy driving a motor. Single phase AC motors cannot be reversed unless they contain a second winding, so that that limits you to three phase or DC. Personally, I think a DC motor with a drive would work well in this application. As far as control, a PLC can be found cheaply on eBay and other places. Some of them are even life-safety certified with fault-checking hardware and can be made to do just about anything from running assembly lines at Ford to amusement park rides at Disneyland. Many have integration with motor drives since the same companies tend to make both. The two ways that are standard for this type of mechanism are an encoder and limit switch. A encoder counts the rotations from the motor and using a formula in the PLC, it can figure out where you are and how fast you are rotating. Then it can modify the speed and direction of the drive to put you in the "correct" position in real-time. A limit switch at the end of travel (or at a predefined location mark if it is a continuously rotating system) allows the PLC to correct accumulated errors in its counts. To interlock the system, there should be an E-Stop on both the platform and the ground and a main keyswitch you can use to lock the system when you are away. I would also probably have a pressure switch wired into the seat of a mat underneath you so if you should move out of the "safe" zone then it will stop. To control it you could use a HMI (touchpanel), push buttons, Ethernet, serial, etc. depending on the PLC. There's all sorts of used industrial automation equipment on eBay these days. A great resource I have used for these questions is [URL="http://www.mrplc.com"]Mr. PLC[/URL]. Sounds like it could be a really cool project. [/QUOTE]

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