Originally shared by James Newton We are hearing that a lot of people are

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Originally shared by James Newton

We are hearing that a lot of people are confused by servos… which makes sense because they are complex and there are soooo many options. To help with the confusion, we’ve created a nice block diagram, with input from everyone in the shop… (sorry about those orders that didn’t get shipped when they should have this morning… we promise to get them out after lunch). Let us know if this help, or what is still confusing? Thanks!
http://techref.massmind.org/techref/io/servo/index.htm
P.S. the diagram is clickable at many points, so if you want to learn more, just go to the actual page above, then click on the picture.

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you’re forgot they line back from the motoring controller to them motion controller in case a position can not be reached in time and to ask for the current position, speed and force.

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Minor details were purposely excluded in the interests of clarity. e.g. There would ALSO be an error feedback from the Motor Driver to the Servo Control to account for over temp, etc…

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Does everyone “get” what “Step / Direction” means? Should we add something about that?

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Why would I want to control a servo with STEP+DIR? This isn’t 1998. I’d want to daisy chain them into SPI and give target-position +average speed and speed at destination for all axis at once, have them synchronization among each other and get notified when they are done.

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Utile

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+Marcus Wolschon Well… Marcus… you just go right ahead and do that. Just as one example, the source code for our BOB PID Servo Controller is in github and adding SPI in addition to the existing USART interface wouldn’t be hard for a real programmer, so you can fork away.

In the meantime, nearly every stepper driver out there will continue to accept Step / Direction. And so motion controllers designed to work with them will keep putting out Step / Direction signals. E.g. RAMPS/Marlin, GRBL, Smoothieboard, TinyG, etc… they all put out… what’s that? oh yes… Step and Direction…

So… if y’all wanted a servo system that worked as a drop in replacement for an existing stepper based device, you would use… what? I’m sorry, I couldn’t hear you? Oh, right. STEP / DIRECTION.

Now, it may be, based on your comment, that you were actually talking about the Motion control part… e.g. wanting to send waypoints to the Motion controller… via SPI? Whatever. There are lots of open source motion controllers so again, fork it.