Considering EMC2 for one of our projects

[Chaka]

I am considering EMC2 for one of our projects. My hope here is to get some general feedback from form users and even possibly build some work relationships.

The question is, how do I leverage EMC2 ‘s advantages while address some of the weaknesses inherit to a noncommercial GPL offerings?


The project is to upgrade proprietary medical manufacturing equipment that drills a series of holes in a product while rotating a table. The original solution is 15+ years old and is made from custom designed motion controller that uses stepper motors and drives in an open loop configuration. These things look a lot like a hobby mill that uses a rotating table vice. Or, like a four axis machine that doesn't’t use the y axis. With a terrible little four line display and custom interface, not CNC.

We sold the customer on a gCode CNC solution. They have CNC machines on staff, owing Master CAM. They just get it.

[Seb]

Weaknesses
-We have never integrated EMC with a machine

I've never integrated a machine either, but I've read the EMC2 docs for machine builders and integrators and now I think it's going to be pretty easy. The docs are excellent. http://www.linuxcnc.org/docs/

-No for hire source of expertise identified
-For design recommendations
-Support for install configurations and customization

Have you checked out the emc-users mailing list and the #emc irc channel? The contact information is in the "Communication" section on the Wiki: http://wiki.linuxcnc.org/cgi-bin/emcinfo.pl

Support in the open-source world is a bit different from the usual for-pay support you get from places like Microsoft. Here in the open-source world, developers and expert users double as the front-line support. The basic questions get asked frequently, so novice users are expected to do their homework by reading documentation and searching mailing list archives. Deep, detailed questions usually get rapid support from a team of experts.

Also, it's not unheard of for EMC2 developers to do for-pay contracts... ;-)

-Perception that no cost is low value

That's so twentieth century! Classic scarcity-based theories of value don't apply to open-source software. Think instead of the value provided by volunteer firefighters.

[stustev]

what's your project?

[Karl_T]

I'd suggest you take a look at Camsoft. This sort of project goes right to its strength.

Karl

[Ray Henry]

The project is to upgrade proprietary medical manufacturing equipment that drills a series of holes in a product while rotating a table. The original solution is 15+ years old and is made from custom designed motion controller that uses stepper motors and drives in an open loop configuration. These things look a lot like a hobby mill that uses a rotating table vice. Or, like a four axis machine that doesn't’t use the y axis. With a terrible little four line display and custom interface, not CNC.

Are you concerned about open loop. Does that mean that this machine is NOT running error free? If it is messing up parts then the customer will need a much more complete overhaul then I suggest below.

I've fitted or retrofitted quite a few machines using EMC/EMC2 and this sounds like an excellent candidate for an update to EMC2. I'd start by opening the control box and look at the stepper drivers. You could take a picture of these and post here. Unless you plan to replace the stepper motor drives, you're looking for some indication of the kind of signals that produce motion. Step and direction is the most common and probably the easiest to understand.

If the electronics are an unintelligible mess then it is probably the easiest to start over with a good parport breakout card and new drives. If you do this then you need to look at the motors and figure out what current they require for proper operation.

The next step is to look at all of the additional IO that is used by the device. Are there limit switches, home switches, cycle start buttons, and feedrate or spindle speed override pots.

Now you are ready to seek out and mate up components that will allow you to handle each part of the retrofit. If the task is simple enough that a single parport can handle the task then the EMC2 software can be easily configured using stepconf. If extra IO is needed, a second parport or a internal or external card solution could be used.

I'd start with a three hole punch, a ring binder, and a good PC printer. There is no substitute for a written path back through the task. Add in pictures, manuals, thoughts, and decisions. I can just hear some folk say, "Paper! How quaint!" The fact is that paper and pencil can be a real advantage as you wire and test because you can scribble notes and drawings much more quickly than you can sit down and type.

A quick side note. This machine is probably CNC or NC at least. Many machines from the 80's and 90's used minimal displays for operator interface. The type of display is not really definitive.

Last question, "What is your relationship to the customer?" You say you sold him on the idea of CNC. Are you a retrofitter or a relative?

Hope this helps.

[Chaka]

I agree that closed loop is better then open loop. In this case the customer is basing the requirements off of the existing solution. The high costs of repairs on an old microcircuit design have basically forced them to implement a new motion control solution. The customer is relying on their inspection technicians to determine whether the product meets specifications.

As a control systems integrator we seldom integrate stepper solutions due to the torque requirements of larger industrial applications, instead we typically use servos. Our experience with using encoders with stepper motors is actually limited. I think that is making our electrical engineers a little hesitant to sell the customer on closed loop stepper solutions it at this point, thinking that the encoder may have trouble getting enough resolution. We will probably want to consider the possible addition of encoders, anticipating this would be good step in design. The great thing about integrating a CNC control as opposed to a property motion solution is that you can wow your customer, with additions like closed loop control, for very little cost. Upfront, they are just scared that they are moving away from the OEM manufacturer of the machine. Sometimes, the customer can't believe that they can get all of that, especially, after being gouged for years.

We quoted this job assuming that we would replace the stepper drives and keep the motors. We also assumed that we would make new control panels, using new breakouts, and Optically Isolated IO.

As far as the project and the customer go. I haven't met this new customer. The job has been sold. The sale was made based off of our previous success with CamSoft. I have been pushing to go with EMC. My background is in software development, form day one with CamSoft, I saw things that set off red flags for me.

Moving away from CamSoft put more money in the budget for configuration. Right now, I trying to convince people that EMC is not just for hobbyists. My hope was that I would find someone here with ties to the project to consult or contract with us if needed.

I will post a picture of this proprietary controller when it comes in to our shop.

Yea, we have paper too. The job file is sitting on my desk. We have job files on our file server as well. I want to pass that file along to our engineers. I would just hate to see this thing go CamSoft, especially due to that there are a dozen more to follow.

[Chaka]

Thank you for your comments. To answer your last question first, we are a control systems integrator and CNC retrofitter. We have done a bout 6 Cam-Soft applications ranging from a 3 axis drilling table to a Bridgeport to a large 5 axis welding fixture. The project we are currently looking at could be done with Cam-Soft but it seems like overkill.

The EMC software looks like a good fit but we need to satisfy ourselves that it will provide a stable and reliable product for the application. This is more than a home hobbyist application intended to product some serious medical products. If this application works well, there could be 12 duplicate machines to follow.

We do intend to replace the stepper drives and other electrics completely so that reuse interfacing would not be a problem. The existing 23 frame stepper motors would remain. A 19”rack mount half size Intel dual-core Pentium PC would be mounted in a desk top Bud style rack enclosure along with a custom designed 19” rack mounted stepper drive and I/O chassis assembly. This assembly plus a monitor & keyboard would replace the existing OEM’s proprietary control box.

The actual programming sequence will be simple with only point-to-point moves and drill sequences plus spindle on-off and clamp controls.

Let us know if you think the EMC software is a good fit.

[Seb]

http://www.youtube.com/watch?v=35tHYaDUmZQ]This is not exactly a hobby-class machine...

[MrWild]

Spending way too much money when you don't need to. A pentium dual core in a rack mount no less.... then again, a new computer is a dual core now-a-days. Size 23 frame steppers will run just fine on a Gecko G540. While small and seemingly hobby grade due to their size, they are state of the art surface mounted drives. The best part is that you get four drives, AND a break out board.

You've probably quoted a Camsoft size retrofit bill, but the reality is that the outlay ISN'T needed. The truth is, you're making more work for yourselves than is needed and spending more than is required. The less you spend while retaining quality, the more you pocket for your company. EMC2 and Gecko G540. Quite a combo.

[Chaka]

http://www.logicsupply.com/products/lf_gs_l05

I need to make few waves on this project as possible. So, I went with something we are ordering on another project.

In my experience fanless is good in all environments. The more air flow is increases the more dust and dirt that are collected.

[Ray Henry]

http://www.logicsupply.com/products/lf_gs_l05

I need to make few waves on this project as possible. So, I went with something we are ordering on another project.

In my experience fanless is good in all environments. The more air flow is increases the more dust and dirt that are collected.

Sounds like you've got a handle on the project. I'd grab a EMC2 bootable CD and test that PC before you get to far with it. I've not heard of anyone testing with the atom processor. If it boots and seems okay, then I'd try the latency test. If it works please add that system to the latency test page.

[Chaka]

Apparently this thing's controller is actually from Omeron. If you mixed and matched the right hardware you could actually get it to intemperate gCode. It still needs to go.

We are still not sure what drives we are going to use, apparently this setup does micro stepping.