Messages

781

General Mach Discussion / Re: Really need help

« on: August 14, 2009, 02:38:37 PM »

Tom, first there is nothing wrong with being ignorant about something, we all started out at the same place in CNC. I was also not trying to be offensive to anyone. My comment about ignorance was directed to another persons comment (the quoted one) saying that if he or others didn't know what an 'RF isolator' was then you probably didn't need it. I was trying to say that the ignorance of others should not be a determining factor in your decisions. Get the facts, as you are trying to do, and make the best decisions you can.

782

General Mach Discussion / Re: Really need help

« on: August 14, 2009, 01:33:53 PM »

So, what is an RF isolator? . . answer; something you probably don't need. If nobody here knows what it is . . . .  likely you aren't going to need it.

That is kind of an odd attitude. Ignorance on your or other folks part should never be a determining factor. 

Tom - The RF isolation BOB you have looks interesting. I went and looked up the types of isolation IC's it uses and they seem like it would work well, it is just a newer style of isolation. It accomplishes the same things as an optically isolated BOB but used Radio Frequencies instead of light.

783

SmoothStepper USB / Re: Does it reduce CPU load ?

« on: August 14, 2009, 08:35:31 AM »

The SS itself is $155, you'll need the correct cables to fit your application too. If your replacing a parallel port you'll likely want the LPH26 to DB25 cable. Take a look here: http://soigeneris.com/Warp9.aspx

784

General Mach Discussion / Re: Really need help

« on: August 13, 2009, 05:14:26 PM »

The scope is what you need so you can measure the pulse width regularity. Compare the pulse width with what your drives expect to see. Feel free to contact me (follow link in signature) if you have any other questions, or just post them here

785

General Mach Discussion / Re: Really need help

« on: August 13, 2009, 04:44:45 PM »

Problems missing steps can be from a variety of things. It can be related to tuning, the PC not putting out a smooth pulse stream, the drivers expecting a long(er) pulse width, etc. A slight 'tick' sound when the motors are running is a good indication of the pulse stream not being smooth enough. The only way to tell is with an o-scope. Mach's Driver Test will test the interrupt latency of the PC but it cannot test the actual PC's hardware's capability of pulsing a parallel port that fast. Even new motherboards and add-on parallel port cards can fail to work properly.

A hardware based pulse generator like the SmoothStepper moves all the timing critical stuff off the PC and onto hardware that can very precisely generate a smooth and stable pulse stream faster than any of us would probably have a need for. I recommend a SS with all the systems I sell and I have yet to have sold a SmoothStepper and have an unhappy customer.

When you get a chance to look at the pulse stream with a scope it will give you a good idea of what the PC is able to do. Also look at data sheet for your drivers and see what the minimum pulse width is that they expect to see.

786

SmoothStepper USB / Re: Does it reduce CPU load ?

« on: August 13, 2009, 04:15:31 PM »

It is very easy to install. You plug it in, point the Found New Hardware Wizard to SS driver file, install the SS Plug-in for Mach 3 and then tell Mach to use the SS as your motion control device. After that you will need to configure the SS for the proper update freq for each axis and the velocity update rate. Ports&Pins settings etc are all done in Mach 3.

I have a more detailed set of instructions that I send out with each SS I sell...

787

SmoothStepper USB / Re: When, Oh When, are we going to get backlash compensation?

« on: August 13, 2009, 12:02:26 PM »

What is abandoned?? Is the SS/Galil/DSPMC all abandoned because they don't have backlash comp that works with Mach 3? The solution is in the works and it will be a better solution for all.

788

General Mach Discussion / Re: We need Linux port

« on: August 13, 2009, 11:59:21 AM »

Well, you have to define what 'real-time' is. and if your Bill Clinton you also have to define what 'is' is. 

Loosely speaking 'Real-time' could be taken to mean that the information was available in a timely enough manner to be able to make a decision based on that information and act on it ,effecting the outcome. In other words the information is deterministic and timely so that the control loop can be respond quickly enough to have an effect on the situation.

As for a Linux port of mach all I can say is BAH! If *nix is your thing then EMC is for you. If you want a CNC control that just works and lets you make parts without all the headaches and heartaches of dealing with *nix then mach is for you.

789

General Mach Discussion / Re: Pico Motherboard a Good Option??

« on: August 13, 2009, 08:07:28 AM »

If you have a noisy systems you will have problems no matter what (SS or not). Things like spindle motors, pump motors, etc all generate lots of noise. I have found a good line filter:http://soigeneris.com/cncparts2.aspx , mounted in the mains feed as close to the source of the noise is the best way to get the noise out. Also, properly routing your cables, keeping the noisy lines away from low signal sensor lines will help a bunch too.

790

SmoothStepper USB / Re: When, Oh When, are we going to get backlash compensation?

« on: August 10, 2009, 09:50:43 PM »

I was just giving you a hard time Rich 

The problem is how backlash comp was added to Mach. It was done in the LPT driver not in the trajectory planner. This not only causes problems for LPT users as if your not very careful with your settings backlash comp can try to over accelerate your motors, it also makes it a huge task for any add-on motion control board to do as it will run into the same issues of possibly trying to over accelerate an axis to try and keep up with what Mach is asking it to do. In fact I'm not aware of any (open loop) motion control card that works with Mach that does backlash comp either.

As I understand things backlash comp is being moved into the trajectory planner (where it should be) so that ANY motion control device and take advantage of it and they should all then use the same exact settings and tunings in Mach (instead of each motion control device trying to implement its own backlash comp all with their own settings/tunings.) In the end I think it will be a better solution for all mach users. It just stinks to have to wait though.