Stepper Motor Driver Help - Recommendation

Hello PLCTalk friends, I have a question about stepper motors and drivers.

I will likely have to be setting up steppers at work to control a high speed packaging machine (small nutraceutical stick cartoning machine - inserts sticks into pack and then folds)to control the guide rails in the feed conveyor where the whole process happens. The stepper motor will adjust either in or out (cw/ccw) to control a mechanical linkage to control different width setpoints of the guide rail for the different carton sizes (to prevent jamming and let the boxes travel through at a fixed width). (I plan on leaving 1 guide rail fixed in place, and the other adjustable with the stepper motor and mechanical linkage.)

The idea is to have this programmable from a small HMI without a PLC and have ASCII commands go to the the stepper driver that an operator or myself can program for width setpoints that work best for the specific carton size to induct into the machine, instead of having an operator have to fiddle with mechanical changes and trial and error every time a changeover occurs.

My question is.....

Of the ones who have a lot of experience with stepper motor controls, what are the most popular stepper motors and drivers that you would recommend as far as software capabilities and networking capabilities, while also considering price? I have searched online for quite a few different manufacturers, and the ones that I like most (and have some experience with at past jobs) are the vexta/oriental motor co drivers and motors. Mainly the CRK series since the software is free, looks pretty user friendly, and the drivers have networking capabilities up to 16 axes of motion.

I would also prefer something that is easily compatible and integrated with CNC motion control systems like Mach3 for experiments that I would like to setup in the future.

Any help or info would be appreciated greatly. Thanks for your input, and HAPPY NEW YEAR!

Vexta series[with pulse/direction control] have served us well, but there are plenty I guess, but never work with any with ASCII comm capabilities.

Regards

chavak said:

Vexta series[with pulse/direction control] have served us well, but there are plenty I guess, but never work with any with ASCII comm capabilities.

Regards

Click to expand...

Thanks for the feedback chavak. What applications do you mainly use them for?


Automation Direct has one that's really easy to send ASCII commands to (and it's cheap), but I don't think it has all the extra software options like Vexta CRK.

Also, if I wanted to use a PLC from Allen Bradley, I can setup a Slick 500 to do some ASCII writes and leave the PLC on the machine for future retrofits.


I'm leaning towards selecting them (OM/Vexta) as my primary supplier of stepper motors and drivers, unless there is someone else who browses this forum that's a sales engineer for a stepper motor/driver company and has a good recommendation?

I like Lin Engineering for stepper motors and drivers. They are good at matching a motor to your circumstances; voltage, amperage, mechanical constraints, etc... Call them - their application engineers are very helpful.

I've paired their R710 drive with AutomationDirect PLCs to good effect. It sounds like you don't need super-featured motion control; AD's DL-05 and DL-06 have built in basic motion control for running steppers. Add an absolute encoder to the stepper shaft, and you have a low-cost closed loop motion control system that never needs homing.



-rpoet

I don't have a lot of experience with steppers, but I did install a Automation direct w/ a red lion display last year. Once I got past some initial communications problems (which took a couple of days), it worked very well. I made some scripts to send the ascii commands to the drive, and the user can create a program for an index pattern to the machine, which is backed up in a CSV file.

After years of using servo motors and drives for most motion control applications, we've recently started using steppers for some of these projects. We standardized on Oriental (RK series) due to our experience with some of their other products.

The results have been very good. I find that steppers can offer a lower cost, simpler solution compared to servos when applied and sized properly. The RK drive is essentially the AC version of the 5-phase CRK without the built-in controller. For step/direction control, we typically use the pulse train outputs of an Allen-Bradley Micrologix PLC, or one of the AMCI motion cards. The nice thing about the AMCI modules is that most of them have encoder inputs for position verification. To me, having all of the motion logic integrated in the PLC is preferable to trying to communicate with an external controller.

Missed steps are the thing to watch out for. Torque drops off with RPM, which is why I like the AC drive since higher voltage alleviates this somewhat. Even with proper sizing, be careful with shock loads as this can cause missed steps. Encoders can detect this but only for notification purposes; you can't do true closed-loop control with a stepper. The Oriental AlphaStep claims to do this but I'm not sure how it works. Usually when you start missing steps you have to stop the motion completely to regain control.

Applications we've done with steppers include driving metering pumps and manipulating pick & place tooling. These both used gearheads on the motors which reduces the torque vs. RPM problem. Recently I've used them on ballscrew-driven actuators for linear motion. This has worked well also but it's important to use a coarse pitch screw in order to be in the RPM range of the stepper. When we used servo motors in the past with these actuators we'd be in the 4000+ RPM range which is totally out of the question for a stepper.

Oriental is certainly one of the #1 players in the small stepper market. I can't speak for the functionality of their integrated controllers since I haven't used them, but they make solid products. We drive some of the steppers pretty hard and haven't had to replace any yet, with a dozen or so axes in service.