Messages

21

General Mach Discussion / Re: Problem with G540 controller not responding to probe settings

« on: August 07, 2017, 08:40:43 AM »

Hi,
I downloaded and re-read the G540 manual and Peter is spot on, there are 4 available inputs and a probe input, for instance, could be
assigned to any of them.

What had confused me was that pin 15 which is normally available as an input has been used for a fault input to the PC from the G540 and it
would appear that it can't be changed.

Mach3 requires at least one input, an Estop. In default configuration pin 10 is assigned as Estop, which is input#1 for the G540. Probably makes sense
to leave it that way. That means there are now only three inputs left, one you wish to use as a probe so now you're down to two inputs for limits and
home switches. Its going to be a challenge to get all those switches wired in such a way that each can trigger an appropriate function in Mach.

Another alternative to combining all your limit and home switches is to use a second port with a breakout board. You cold then make pins 1-9 inputs
in addition to the regular 10-13 and 15. Inputs to burn!

Craig

The G540 uses pin 15 as the fault input.  It is usual to assign this in Mach3 to the EStop function. When wiring up a controller, it is common practice for the estop mushroom switch to remove power from the controller when pressed. When power is removed from the G540, the fault line will activate the Mach3 estop input which is the desired action.
With the G540, you can also use the enable terminal. When you open that, the G540 will assert the fault line putting Mach3 into reset.

As to limits and home switches,  you can wire all the limit switches in series, feeding them into a single G540 input. When the machine runs into a limit switch, Mach3 doesn't care,  which switch was hit, just that one of the limits was hit.

You can also wire the home switches in the same manner, or use the limit switches as the home switches as well. When Mach3 homes it homes a single axis at a time so in this situation is does know which switch was hit. So if it suits your machine configuration, you can use a single G540 input to look after all your limit and home switches.

Have a look at this example schematic I've done for the G540.

http://www.homanndesigns.com/pdfs/EN010_V8.pdf

Cheers,

Peter

22

General Mach Discussion / Re: Problem with G540 controller not responding to probe settings

« on: August 06, 2017, 05:21:35 PM »

The G540 has 4 inputs that can be used for ANY Mach 3 input function (apart from the ESTOP). You can assign your probe pin to any of the four G540 inputs.

23

General Mach Discussion / Re: mach3 license

« on: May 09, 2017, 11:36:54 PM »

Hi
If you do not have the original license file  sent to you when you purchased it, contact the seller as they may have it on file. Otherwise contact Mach3 support as they should be able to sort you out.

Once you have the license file, place it into the Mach3 directory. This is usually C:\mach3

To get the Mach3 software download it from the Mach support site.

Cheers
Peter

24

General Mach Discussion / Re: Ports and Pins and Homing - G540

« on: February 04, 2017, 04:26:34 PM »

Hi,

It's quite simple really. Mach3 homes one axis at a time. So as it homes an axis, and the input with the X/Y/Z in series switches is activated, it can only be the switch for that axis that caused the activation.

If the machine was homing the Y axis for instance, and you manually pressed the Z home switch with your finger, Mach3 would incorrectly assume that it has hit the Y home switch.

If the same switches are used as limit switches, Mach3 doesn't know which axis tripped the limit switch input as multiple axes are in motion. It doesn't care as it just EStops the machine.

Cheers,

Peter

25

General Mach Discussion / Re: G540 Steps Per

« on: January 30, 2017, 04:18:07 PM »

I understand Gerry, thanks however perhaps Gecko should have put a note somewhere stating the 20000 may not be applicable to all users. I spent more than a day trying to configure my 4 motors to run smooth because I thought if Gecko says to use 20000 they must be right

I'm a bit surprised that you are apportioning blame to Gecko.

The steps per unit value is dependent on the following;

• Micro steps of the stepper drive,
• Steps per revolution of the motor
• Pitch of the lead screw
• Mechanical gearing in the drive train for an axis.

Out of the five variables above, Gecko is responsible for one of them.

If you had read the manual http://www.machsupport.com/wp-content/uploads/2013/02/Mach3Mill_1.84.pdf specifically section 5.5 Tuning Motors you would understand that Gecko would never suggest a value for your machine. It would be clear that the XML profile provided by Gecko sets up the input and output pins for their G540 drive.
They cannot know the steps/per value, or the velocity and acceleration values for your machine or any other machine.

Every Mach3 profile has to have a value in the steps per field. The ones in the profile from Gecko are most probably the values they use for the machine that they created the profile.

As a suggestion, read the manual cover to cover. You may not understand it all but enough will sink in so that it should jog your memory when you have questions.

Cheers,

Peter

26

General Mach Discussion / Re: G540 Steps Per

« on: January 29, 2017, 05:55:02 AM »

4064 is incorrect.

If you have a 10mm pitch leadscrew then with a G5640 the steps/inch is 5080.
The G540 is a 10ustep drive. It is NOT an 8ustep drive.

Peter

27

General Mach Discussion / Re: G540 Steps Per

« on: January 29, 2017, 01:21:47 AM »

I got a new G540 and using the .XML from Gecko (540BVFD) the steps per setting is 20000 which makes my motor running very rough. Using the Mach3 “Set Steps per unit” on the Settings tab it gives me a steps per of 4002 which is pretty close to what I get with my calculations assuming a 1/8 microstepping. (my cals: 200 x 8 x 2.54 = 4064 with 10mm Lead ball screws)

What microsteps the G540 is using and can I change them?

The G540 is a 10uStep drive. You cannot change that. If you have a 100 pitch leadscrew then the steps/unit (mm as that's what your lead screw is) the calculations are;

200steps/rev * 10ustep  = 2000 steps for 1 rev of the motor.

since 1 rev of the motor moves the axis 10mm then we get 2000/10 = 200 steps per mm

If you want to set your native units to imperial, then multiply the 200  * 25.4 = 5080 steps/inch.

Cheers,

Peter

28

General Mach Discussion / Re: Mach3 & G203v W/microstepping how to have DRO'S read in .00002" increments?

« on: January 06, 2017, 05:01:25 PM »

Regardless of the intent of microstepping, as I understand it, 10x MS should fool the motor into thinking it has correct windings/magnets etc to have 2000 steps per rev. At 2000 steps per rev, the X axis motor would move .18 degrees per step. At a ratio of 2:5, the ballscrew is driven .072 degrees. 360 degrees of rotation at the ballscrew moves the X axis .100".  360/.072deg = 5000. .100"/5000=.00002"

If my math is correct (and frankly, its always been suspect) the X axis can be moved .00002" per step.

I get that the intent may be different than you think microstepping was designed for, but all I am doing is (effectively) "electronically" gearing down the motor.

The G901X step multiplier does the exact opposite of what you want it to do. it multiplies the number of steps it receives. The four settings of the G901X work as follows;

• Full Step  - For each step the drive receives the G901X issues 10 steps resulting in a 200 steps/rev motor
• Half Step - For each step the drive receives the G901X issues 5 steps resulting in a 400 steps/rev motor
• 5 uStep   - For each step the drive receives the G901X issues 2 steps resulting in a 1000 steps/rev motor
• 10 uStep - For each step the drive receives the G901X issues  a single step resulting in a 2000 steps/rev motor

The G203V without the multiplier board is a 10uStep drive giving  2000 steps/rev.The G901X reduces the resolution .

"The result of this is that microsteps are not linear between full steps, so the accuracy is not there." I am not clear on this. did you mean the steps are not linear in that they are not accurate angular movements of the shaft when microstepped? or that the holding power is not linear as it pertains to the differing holding torques available to "real" steps and their associated detents vs. those available to artificial sub steps.

Have a read of this;
http://www.geckodrive.com/support/step-motor-basics/accuracy-and-resolution.html

"The accuracy of the machine should be the distance that an axis moves for a full step" Why? if I can make the motor turn in 2000 steps, with my gearing ratio, I will get a movement of .00002" correct? that is after all the goal.

See above. The full step position is the only true accurate position. resolution is not accuracy.

"The purpose of the G901X microstepping multiplier board is to cater for computers or systems such as PLC or Arduinos that cannot generate a high enough step rate. So you should remove the step multiplier board from the G203V." Again, regardless of the designers intent, if 10x microstepping makes a move of .00002", their intent is irrelevant to me.

The G901X reduces resolution rather than increase it.

"The best way to get the accuracy you need is to mechanically gear down the axis with belts so that the accuracy of a fullstep position provides the accuracy you need." Not sure I follow. The "best" way is one that works, as I intend it to. If it involves a step pulse multiplier, so be it.

I agree that the best way is the one that works. Unfortunately the step multiplier is not one of the ways, nor is relying on microstepping.


Microstepping way first used by astronomers. The needed a way to smooth out the stepper motion as they used stepper motors to drive telescope tracking systems. Microstepping was designed to smoother the motor movement at low speeds. It was never intended to improve the position accuracy of the motor.

Cheers,

Peter

29

General Mach Discussion / Re: Mach3 & G203v W/microstepping how to have DRO'S read in .00002" increments?

« on: January 05, 2017, 06:23:05 PM »

Hi Nate,

You are approaching this the wrong way. Your making a number of assumptions that are incorrect.

• Standard stepper motors are 200 steps/revolution (1.8 deg/ step). At each of these poles (full step position) there is a magnet pulling the rotor to this pole. The position of the rotor at this pole is very accurate.  To position the rotor between the poles is called micro stepping. It is performed by applying a percentage of the full step current (Sine and Cosine) to each of the stepper coils  so that the magnetic fields "pull" the rotor away from the full step position.  You can envisage the two magnetic fields as two springs holding the rotor in position. The Gecko drives are 10 micro step drives. So each micro step theoretically moves the rotor 1/10 of 1.8 degrees, or 0.1degrees. In practice this is not what happens for a couple of reasons.
  
  • The Stepper detent force is pulling the rotor towards the full step position
  • The 2 magnetic fields will not be exactly at the theoretical strength. This is due to slight variations in the stepper motor coil winding, the driver current, etc.
• The mechanical friction in the drive systems (stiction)

The result of this is that microsteps are not linear between full steps, so the accuracy is not there. In fact if you move the axis by a single microstep, the axis will most likely not even move. The sole purpose of microsteps is to smooth out the motion as low speeds. It is not there to improve the accuracy.
The accuracy of the machine should be the distance that an axis moves for a full step. If you are really desperate you could use the 1/2 step distance as both coils are likely to be reasonably identical, the full step detent force is the same on both side of the position. That said, remembering that the rotor is held in position by the two magnetic fields, the axis may be pushed off it's position by the cutting/grinding forces. The detent magnet at the fullstep position helps to avoid this.

The other concern is that if you are using the G901X plug in multiplier board, it REDUCES the resolution, rather than increasing it. As it comes the G203V is a 10 microstepping drive. When you plug in the multiplier board and set it to say, the 5 micro step position, the board will produces two micro steps for every step it receives. If you set it to the full step position, it will generate 10 microsteps for every step you send to the drive.

The purpose of the G901X microstepping multiplier board is to cater for computers or systems such as PLC or Arduinos that cannot generate a high enough step rate. So you should remove the step multiplier board from the G203V.

The best way to get the accuracy you need is to mechanically gear down the axis with belts so that the accuracy of a fullstep position provides the accuracy you need.

There are also stepper motors that are 0.9degrees/step rather than the common 1.8degrees/step. These will double your stepper accuracy.


As to increasing the accuracy of the Mach3 DROs, you need to edit the screen and add another decimal place to the DRO.

Cheers,

Peter

30

General Mach Discussion / Re: PWM Spindle Control using Mach3 - How I did it

« on: October 29, 2016, 07:42:59 PM »

Hi,

I don't have experience with this particular controller, but you may be able to get it to work.

I mainly use KB electronic controllers. The KBIC-125 below or similar should be suitable for your motor.

http://www.ebay.com/itm/KB-Electronics-KBIC-125-1-5-HP-90-VDC-OUT-115-AC-IN-MOTOR-SPEED-CONTROL/231944525239

You could then use a DC-03 Digispeed to then control it from Mach3.

http://www.homanndesigns.com/index.php?main_page=product_info&cPath=54_1&products_id=21

Cheers,

Peter