Upgrading an existing servo system

[fizgig]

The servo system I currently use to move a small carriage back and forth on a track is this one:

http://www.cadcamcadcam.com/index.asp?PageAction=VIEWPROD&ProdID=62

You can see the little driver card at the bottom listed as an option which I also have.

This setup is nice because the driver card has only two TTL inputs: "pulse" and "direction" which I was able to easily use with my microcontroller. The driver card connects to the encoder on the motor as well as the two motor power leads and just takes care of everything.

The trouble is, I need more torque. This system is rated for 170 oz-in of stall torque and, of course, it drops when I ramp up to as high as 300RPM. 170oz-in of stall torque works great but I need to find a motor/driver that can sustain it up to the 300RPM. Adding in a little more power as a cushion wouldn't hurt either.

Does anyone know of a place that sells a reasonably-priced system that has the required torque that just needs me to give it a pulse and direction? I have found motor/driver combos that have RS485 that you give commands through but that's a bit too complicated for me...I'm just trying to make the motor stronger - not more complicated.

Thanks!

 

[itsmoked]

That is a really nice unit there.

Is this for a mill? I think you are going to have problems. The control shafts have torque limits. They are designed for a human hand to turn. 170oz-in is quite substantial. Trying to increase this would probably require 3/8" shafts and larger bearings or result in a mechanical failure.

I guess you realize this but you will also likely need a different controller to deliver more power. An a larger power supply to provide the increased power demands.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[fizgig]

The unit I mentioned is indeed designed for use in a DIY mill but I'm using it in another application - I'm using it to drive a gear which drives a chain which drives a carriage back and forth on a track I've made.

As such, I'm limited to the strength of the chain which is quite high.

I'm wondering if there is a similarly simple but yet more powerful system that resembles the link I posted.

 

[itsmoked]

Do you need the hand knob too?

Keith Cress
kcress -

http://www.flaminsystems.com

 

[fizgig]

Nope, the hand knob actually doesn't ship with it.

In addition, I've replaced the belt reducer with a mini-gearbox with about the same ratio of 3:1 so it's a lot tougher now.

I've attached a pic of what I'm talking about. The red gear drives the chain.

 

[itsmoked]

Ok good. I see.

You need the motor?
You need it encoder'd?
You need the drive/amplifier?

And you need the drive to take in the encoder input to keep the shaft fed back? And you want to drive the unit via a direction and a pulse/step? If so what drive signal do you have? TTL?

Keith Cress
kcress -

http://www.flaminsystems.com

 

[mikek10]

Lots of people can do what you need, my curreny fave is baldor. Ask for stuart calvert

 

[fizgig]

@mikek10: I'm sure that's the case but it's hard to find a system that has a simple TTL pulse and direction input with all else being handled by the driver/controller. I have found complex serial-speaking controllers but I want the simpler two TTL input solution. I haven't checked Baldor yet, I'll look them up. Thanks for the suggestion.

@itsmoked: I need the motor, encoder and all circuitry required so that all I have to do is supply a TTL pulse signal and a TTL direction signal. In other words, I don't want to have to read the feedback in my microcontroller, I'd rather have the driver that comes with the system do that.

 

[itsmoked]

Have you looked at

http://web3.automationdirect.com/static/specs/sureservoselection.pdf

Your existing unit is about 50W of drive.

The smallest of the above is 100W which puts you on the inexpensive end. They seem to come with pulse and direction inputs.

Keith Cress
kcress -

http://www.flaminsystems.com