Messages

601

General Mach Discussion / Re: Power Supply Unit

« on: February 16, 2011, 09:58:14 PM »

Do NOT remove the clear plastic.

Wires can be at the top or the bottom - doesn't matter.

Put one rubber piece on the mounting surface, then the transformer, then the other rubber piece, followed by the large metal washer, then install the bolt.  Do NOT over-tighten the bolt - just enough to keep the transformer from going anywhere.

If you're AC source is 110/120V, connect the Violet and Blue wires together, and connect to one side of the AC supply.  Connect the Brown and Gray together, and connect to the other side of the AC source.  If your AC source is 220/240V, connect the Brown wire to one side of the AC source, and the Blue wire to the other side.  Connect the Violet and Gray wires together, and seal the connection up in some heat-shrink tubing.

Connect the Orange and Black wires together, and connect to one AC input of the rectifier.  Connect the Red and Black wires together, and connect to the other AC input of the rectifier.  Connect the capacitors with the - terminals to the - terminal of the rectifier, and the capacitor + terminal to the + terminal of the rectifier.

Regards,
Ray L.

602

General Mach Discussion / Re: Power Supply Unit

« on: February 15, 2011, 11:54:07 PM »

None of them should generate a great deal of heat.  Heat sink the rectifier, just in case.  The transformer should only get hot if you run it for sustained periods at high current output, which should never happen.  The capacitors should NEVER get hot.

Regards,
Ray L.

603

General Mach Discussion / Re: Closed loop options?

« on: February 15, 2011, 09:53:08 PM »

You might want to look at EMC instead of Mach3 as your controller software.  It closes the loop in the PC, and there are pretty inexpensive interface boards available to connect directly to +/-10V drives.

Regards,
Ray L.

604

General Mach Discussion / Re: Motor Max Speed problem

« on: February 14, 2011, 09:58:14 PM »

I would guess the problem may well be the Breakout board.  I suspect you're seeing the upper limit of the step pulse frequency it will pass through, and beyond that point the step pulses are "aliasing", so the frequency coming out of the BOB is lower than the frequency going in.  CNC4PC uses some strange pulse-shaping circuitry on their boards that I could see causing that kind of problem if you've got a defective chip or component on the board.  It would be instructive to try temporarily wiring up a different breakout board, or even a completely passive one, just on a single drive, and see what happens.

Regards,
Ray L.

605

General Mach Discussion / Re: Strange problem in Circle

« on: February 13, 2011, 10:04:48 AM »

That's not a problem in Mach3.  Your machine has a large amount of backlash in the X axis....

Regards,
Ray L.

606

General Mach Discussion / Re: .300" overshoot at 40"/min when using feed hold

« on: February 11, 2011, 09:25:04 PM »

I don't understand what the problem is....  If you want it to stop RIGHT NOW, you press Stop.  But, if you do so, and it's moving fast, you may, or may not, lose position, as Mach3 simply stops outputting step pulses - there is no deceleration at all.  With steppers, you're pretty much guaranteed to lose position.  With servos, you may, or may not lose position, depending on how fast the machine was moving, how much following error your servo drives allow before faulting, and the servo tuning.  If you press FeedHold, the machine does NOT stop immediately.  It stops when it's convenient for Mach3 to stop.  This means it's likely to complete the current segment, and it will decelerate to a stop, so it WILL move some distance before all motion stops.  The faster you're moving, the further it will move.  This is not a bug, it is how it is designed to work.

Regards,
Ray L.

607

General Mach Discussion / Re: Macro Help

« on: February 11, 2011, 01:22:58 AM »

http://www.machsupport.com/docs/Mach3_V3.x_Macro_Prog_Ref.pdf

608

General Mach Discussion / Re: Power Supply Unit

« on: February 09, 2011, 12:41:07 AM »

Perhaps your other supply simply has a defective temperature sensor?  Is the air coming out of the supply warm?

Go to Radio Shack, or any electronics store, and buy a small tube of silicone heat sink grease.  Put a thin coating on the underside of the rectifier, and bolt it yo your metal enclosure.

If Hood sent you those caps, I"m sure they're fine.  The dashed line running up the side is the minus indicator, so the near terminal is the minus.

Regards,
Ray L.

609

General Mach Discussion / Re: Power Supply Unit

« on: February 08, 2011, 11:42:15 PM »

The information you were given in that other thread is absolutely incorrect.  If it were, you'd have to put twice as much power into the input of the supply as you get from the output, which is NOT the case.  The supply will NOT be dissipating 250W.  The only significant power dissipation in the supply itself will be in the bridge rectifier, which may be dissipating a few watts, and that only when the supply is providing high current to the motors, which it should never be doing for very long.  It should be heat-sinked (i.e. - mounted to a metal plate, smeared with silicone grease at the interface). 

Those are some gnarly looking capacitors.  How old and.or abused are they?  Old electrolytic caps do not perform well, and can go "boom".  On the blue plastic sleeve you should see a minus sign, or a string of them, running the length of the capacitor, near one of the terminals.  That is the minus terminal.  Do NOT power it up unless you are certain it's connected correctly, or it WILL go BOOM as soon as you apply power!

Regards,
Ray L.

610

General Mach Discussion / Re: Another dumb question

« on: January 30, 2011, 11:27:47 PM »

Yes DSPMC is closed loop just like my servo drives close the loop to my AC motors but if the pulse is stopped immediately without the deceleration then the motors may end up out of position from where Mach thinks they are.
Hood

With servos, this should not be a problem, unless you're moving fast enough that when the step pulses stop the axis coasts far enough, due to inertia, to trigger a servo fault due to exceeding the maximum allowable following error.  Barring that, it should overshoot, then quickly return to the position Mach3 thinks it's in.  On my servo-driven knee mill, I can usually hit Stop without losing position, even when doing a rapid.  The same is NOT true of steppers, however.

Regards,
Ray L.