Messages

31

General Mach Discussion / Re: stepped motor soft start

« on: May 01, 2012, 06:28:42 PM »

Stepper motors do make noise. You are hearing the the motor line up the magnetic poles. At low speeds you have max torque and the noise is louder than at higher speeds. The other reason for the noise can also be mechanical/structural. The machine structure is resonating and amplifying the sound of the motors. Its a fact of life with steppers. Stiffen up your motor mounts.

32

General Mach Discussion / Re: G91 and others problems

« on: May 19, 2011, 10:05:47 AM »

Can you create programs that are in G90 - Absolute Positioning? I understand that some are used to working in incremental (G91), but I always found absolute (G90) easier to keep track of where I was in the program and on the part.

33

General Mach Discussion / Re: Yes, another home limit switch question.

« on: May 19, 2011, 10:02:10 AM »

Another way that might be easier to troubleshoot is to use 3 inputs, 1 for each axis.  You can use 2 limits for each axis, wired normally closed wired to each input. set the positive, negative and home to the same input. I have a KX 3 that is wired that way, Had a problem when I first tried homing because the X & Z were swapped in the settings. For best results you might want to make sure the limit that is used for home is a good quality switch so the home position doesn't wander...

34

General Mach Discussion / Re: Motor stall killing me!

« on: May 18, 2011, 12:03:18 PM »

I rthink there is a problem here with terminology.

Motor Stall normally means that the stepper motor is either overloaded, or that the step rate is too fast and the motor is not able to generate enough touque. This does not preduce predictable results. It sounds more like you have something slipping. Motors either stall or they don't stall. at low speeds and accelerations your stepper motors should produce the most torque and be very reliable. If you are having problems getting reliable moves you should look at all the mechanical connections first. Are you sure the motor is turning? if so - is the leadscrew turning at teh same rate? Get a marking pen and put some marks on shafts and connectors and make sure they are not slipping relative to each other. Make sure that the belts are properly tightened. is this only happening on 1 axis?

35

General Mach Discussion / Re: Controlling Mach with Powerpoint? Is this possible?

« on: May 18, 2011, 11:39:48 AM »

Now that you explain it better - you don't need mach - What you need is a program that will display pictures in sequence along with some code to index the table up and down. Got anyone involved that can program in Visual C or Visual Basic? Wouldn't have to be a very complex app, but would probably be less work that trying to create a custom interface between Powerpoint and Mach.

36

General Mach Discussion / Re: y-axis driven by two motors

« on: May 18, 2011, 11:31:49 AM »

You could send the Y-Axis signals to 2 motors, or you could slave the A-Axis to the Y-Axis.

37

General Mach Discussion / Re: Controlling Mach with Powerpoint? Is this possible?

« on: May 16, 2011, 01:29:24 PM »

Sounds like the totally wrong application for powerpoint. Why bother generating your slices to powerpoint when you could just generate them straight to a G-Code file and just run it. What powerpoint hads to do whith this process???

38

General Mach Discussion / Re: problem with the X ais

« on: May 10, 2011, 01:33:31 PM »

Check for any mechanical problems with X. Is it binding when moving in one direction skipping steps? Is something slipping when going in the one direction? Make sure you have no mechanical problems FIRST. Only then can you make any changes in the settings. Does it work at a slower speed? I would assume that both axis have the same hardware, but are they both configured the same on the drives (check the configuration switches)?

39

General Mach Discussion / Re: Hood.....where is he?

« on: May 06, 2011, 04:43:38 PM »

Recover that coin yet???

40

General Mach Discussion / Re: ab pulse train output

« on: May 06, 2011, 04:38:09 PM »

I don't think you'll have much luck driving the motion outputs of the plc from Mach. The high speed functions only work when you are running a motion program from the inside PLC program. When you are using them as normal outputs (which they really would be in this case) there is some limitation as to how fast they can change state. The motion control program that resides in the PLC runs along side the normal PLC I/O function and runs somewaht independent of the normal PLC I/O Scan.  I have seen normal PLC scans of 500-600 per second, where you are looking for output frequencies in 100,000 times a second.

A normal PLC  runs kind of like this - Read the inputs, go through the program logic setting the outputs, write the outputs. The Micrologix PLC's I used did this about 500 times a second. There is some other overhead in the process to check for errors and such...