Printable View
Hello, I am new to this group and have a question. I currently have a CNC router with stepper motors in an open loop configuration. I would like to add encoders and switch to a closed loop configuration. What type of controller is recommended for this? I am willing to build my own if plans/schematics are available.
Thanks in advance,
Ed
One way, you can add a linear scale to your machine as a position feedbakc closed to your motion controller (e.g. PMC).
Another way, by implementting high resolution encoders to update the motor position every 25 micro-seconds, closed-loop stepper drives ensure controled real-time position accuracy without lose of steps in open-loop stepper system.
Go to Leadshine website for more product information
eric can you give us a list of actions required for moving from open to closed loop stepper? I have a 3 axis router with rotary and got problems with losing stepps. I am going to solve it but dont know if change to servo or just add encoders. if adding encoders is possible with no need to any complicated electronics knowledge (I am not on it!) Its what I will do certainly.
Actually, it's hard to add the encoder to the stepper motor by yourself if you are not motor manufacturer for the airproof reason. As I said previous, you can add a linear scale to your machine closed to you motion controller. But this proposal will be charged much.Quote:
Originally Posted by justbabak
Another way, you can use a existing closed loop stepper system (closed loop drive+motor) as a directly replacement of the current system. It combines the advantages of both servo system and open loop stepper. And it's cheaper than servo system. You can go to Leadshine website to get more product information. Reply this if you have other issues.
seems good option, I checked website but I did not find any "closed loop stepper" thing. can you be more specific? thanks in advance.
Hi, Leadshine closed loop stepper products are named as Hybrid Servo Drives and Hybrid Servo Motors. (Hybrid Servo=Closed Loop Stepper) So check the website and find hybrid servo system products.Quote:
Originally Posted by justbabak
ok, I checked it, sounds good, but there is one question, the encoder is absolute or relative? It is important because my problem with the current drive is that it makes a small dislocating movement upon power-on! so after a power failure or after each start-up of the machine, all the axes make a small move (between 0-0.2mm) unexpectedly so I have to adjust all the coordinates again.
so I have to makes sure that the new drive system which I want to move on will solve this problem. does it solve it?
I checked with Leadshine R&D and the hybrid servo(clsoed loop stepper) products only support relative encoder type now. The absolute type product is in the process.Quote:
Originally Posted by justbabak
I have met some CNC machine maker which used the relative encoder before. All the axes of the machine will homing first after power-on to fix the problem you mentioned. I know it's unconvenience than absolute type.
thanks Eric for shedding some light on this subject, now the conditions are more clear for me.
It's OK. If you have further problem or have any interest with Leadshine hybrid servo(closed loop stepper) products, please kindly contact me at [email protected] or visit Leadshine Technology Co., Ltd. - the leading global motion control product manufacturerQuote:
Originally Posted by justbabak
What would be the best to replace IMS drives for steppers with US Digital encoders?I am turning a Beckman pipetter into a 3d printer.
Hello Leadshine Eric...
If we are currently using Nema 34 Steppers rated at 960 oz holding torque... what model and specification drivers and hybrid stepper would your recommend. I have seen some rated at 2Nm but that seems like almost 1/3 of the power of a 960oz motor.
Any advice?
And if I wanted to go to a DC servo motor that had an encoder... what would you recommend then?