Messages

1581

Mach4 General Discussion / Re: Mach 4 scaling and keyboard button mapping

« on: March 29, 2020, 02:04:46 AM »

Hi,

What would it take for me to have MACH4 Feel like MACH 3

Probably not that much....but why? Mach4 is light years ahead of Mach3......I don't want to go back to Mach3,
I'm all for making Mach4 the way I want and to hell with Mach3.

Craig

1582

Mach4 General Discussion / Re: Mach 4 homing

« on: March 29, 2020, 02:00:55 AM »

Hi,

This can be a bit confusing, but is more flexible

Confusing, well perhaps the first time you encounter it but thereafter you see its a QUANTUM leap ahead of
Mach3.....and you haven't even seen the good stuff yet, the mapping and un-mapping on the fly, under program control....
your'e in for treat!!!

Craig

1583

Mach4 General Discussion / Re: Screwcutting issue under Mach4

« on: March 28, 2020, 11:49:08 PM »

Hi,
threading requires a stable spindle speed, the more stable the more accurate the pitch of the result.

The key word here is 'stable', is does not have to be accurate. For instance you might dial up 500 rpm
or so, but whatever non-linearaities results in a speed of 400rpm. Mach will read the actual speed, whatever it is
and then calculate the Z axis progression rate to make the thread. It does not matter to Mach particularly that
the speed is 500 OR 400, so long as it stays the same throughout the operation.

In truth Mach does try to recalculate the Z axis progression on the fly in order to get the right pitch despite spindle
speed variation, however the best result is till had when the spindle speed is constant.

You may be interested to know that Warp9's ESS has a fairly new (six months or so) feature of PID spindle control.
The spindle is fitted with an encoder of some kind, including an index signal, and the PWM output of the ESS is
adjusted under PID control to vary the analogue output with a view to control spindle speed in closed loop fashion.
This is a boon if your spindle is marginally powered or has very little inertia. It must be said that the closed loop
bandwidth is not high, certainly not as high as a position loop servo, but sufficent for an improved spindle speed control
for threading.

If you cannot control the spindle speed in a program or an MDI then threading is a joke. You must solve this lack of
spindle speed control. A PWM to analogue circuit can be made with a resistor and a capacitor (5 cents each) at the simplest,
and with an op amp and a handful of resistors an capacitors (less than $5.00) if you want something a bit flash.

Do you have or have access to an oscilloscope? If you do probe the PWM output of the ESS and see whats happening.
I'm suspicious that the BoB is not set up quite correctly.....everyone else has got PWM to work....why not you?

Craig

1584

Mach4 General Discussion / Re: Screwcutting issue under Mach4

« on: March 28, 2020, 09:35:34 PM »

Hi,
my apologies I was confusing BoBs, the C11 manual clearly shows a PWM to analogue output.
Please disregard my previous post.

Although I'm still interested can you control the speed from MDI?

Craig

1585

Mach4 General Discussion / Re: Screwcutting issue under Mach4

« on: March 28, 2020, 09:32:17 PM »

Hi,

My speed control board (Built in to C11 Bob) only allows for Step pulses.

I didn't think the C11 had a PWM to analogue circuit built in.

If I'm correct then a low duty cycle PWM signal would result in an effective low output, ie dead slow
and a high duty cycle PWM signal would result in a high level output, ie flat out and any
intermediate duty cycle would result in an intermediate speed but could not be called controlled.

Can you control spindle speed from MDI? From what you've described I would guess not.

Craig

1586

Mach4 General Discussion / Re: Mach 4 homing

« on: March 28, 2020, 09:22:45 PM »

Hi,

Also have homing switches on all axis

How exactly do you mean?.

On the master/slave axis do you have a home switch for each motor OR do you have one switch for both?

It makes a difference. When a motor is homed it will drive to its home switch, whether it be a master or slave.
If a motor does not have a home switch assigned to it, it won't move and will just 'home in place'
Could it be this is what is happening? Does the slave motor (motor 3) have a home switch assigned?

There are two reasonable solutions to this. You could have two separate switches at each end of the gantry.
In this case you would have two inputs, one being the home switch for motor 0 and the other being the home switch for
motor 3.

The other way is just to have one home switch on the gantry and both motors share it. I have attached a pic of
how that would look on the Control/Input Signals page. Note that both motor 0 home AND motor 3 home are enabled
but they point to the one input pin, port2 pin10 in my example. That is so say that both are enabled but they monitor
just the one switch.

Clear as mud?

Craig

1587

Mach4 General Discussion / Re: Mach 4 homing

« on: March 28, 2020, 09:03:40 PM »

Hi,
I think there may be some confusion on the Homing/Soft Limits page.

You have nominated the X axis (axis 0) and A axis (axis 3) to home together AFTER the Z axis.
That is to say that both axes are number 2 in the homing order.

Your motor assignments page shows that you don't have an A axis (axis 3). You do have a motor 3, it is
slaved to motor 0 and BOTH are assigned to the X axis (axis 0).

May I suggest reset the homing order  of the A axis (on the Homing/Soft Limits page) from its current '2' to '0',
ie the A axis is not to be homed.

Try it and see.

Craig

1588

General Mach Discussion / Re: Limit switch and home switch question??

« on: March 28, 2020, 05:05:50 PM »

Hi,
the kernel speed is the underlying clock that  Machs parallel port uses to generate pulse streams.
Its default is 25kHz. That is to say that the FASTEST pulse stream it can generate is 25kHz.

In your case what you have done is by using excessive microstepping  (probably) that to achieve your nominated
max velocity would require Mach to produce a pulse stream of faster than 25kHz. Mach is warning you, and that is the
substance of the error.

It won't make a lot of difference, its just that your axis (or axes) won't get to their max speed because Machs
parallel port can't produce a fast enough pulse stream and will go only as fast as 25kHz will take it.

You can increase the kernel speed with a licensed copy of Mach3, but not Demo copies. The faster the kernel speed
often results in Mach stuttering or even crashing. The general rule is to use to SLOWEST kernal speed that
is consistent with your motor tuning. Most PCs will tolerate 35kHz and sometimes 45kHz but many play up at 65kHz
or higher.

If you bought and external motion controller like a UC100, it has an internal frequency of 100kHz, its effective 'kernel
speed', despite it not being called a kernel speed at all.

I use an Ethernet SmoothStepper and its 'kernel speed' is 4MHz ie 160 times faster than Machs parallel port (default speed).

What microstepping have you set your drives to?
What is your 'StepsPerUnit' value?
What is your 'MaxVelocity' value?

Craig

1589

Mach3 under Vista / Re: Can't get the jog pop up in mach3

« on: March 28, 2020, 04:45:23 PM »

Hi,

Will I be able to update the software, or should I upgrade to Mach4?

I am a Mach4 supporter fanatic compulsive....so beware my comments are biased.

As Zasto pointed out you should be able to update Mach3 despite the license not strictly speaking being your own.

Mach3 is still perfectly capable and maybe does some things that Mach4 doesn't, however there are things that Mach4
does which Mach3 cannot do, and many things it does are much more refined and sophisticated than Mach3.

When comes to making parts, at least on typical machines, there is little to pick and chose between Mach3 and Mach4.
They are both equally accurate, equally smooth, equally fast, in fact equal in most respects.

As you probably know all development of Mach3 ceased six years ago, so any bugs Mach3 has will stay that way and
no new features will be added. In more recent times Microsoft updates to Windows 7 and Windows 10 have threatened
to stop Mach3, fortunately a fix has been found for that. The point being is that Mach3 is now an old program and may
be increasingly affected by advances in Windows OS's.

Mach4 is by comparison right up to date with new features being added frequently.

The real advantage of Mach4 is it flexibility to be customized for different machines. This comes about because of
Mach4's modular structure, rich API and its Lua scripting language. Being able to customize is of great value to an OEM
but may have little appeal to you.

I have found, and have seen the same in other hobby users, that a great deal of satisfaction can be had in programming
Mach4 to behave in some specific way that you want. Having said that you don't actually have to do anything to it,
it works pretty much straight out of the box.

My suggestion is to stick with Mach3, if that's what you've got. In the meantime you can download Mach4 for free and 'have a play
with it'. Note that Mach4 all but requires you use an external motion controller like an ESS or UC300, so you would have
to consider the cost of the controller and BoB in addition to the Mach4 license fee if you wanted to to upgrade.

My personal sentiment with respect to Mach4 is 'go mad now and beat the rush!'.

Craig

1590

General Mach Discussion / Re: Limit switch and home switch question??

« on: March 28, 2020, 03:04:25 PM »

Hi,
as I posted earlier most people combine a limit switch and home switch in one.

When you home that axis Mach ignores the limit switch event and treats as a home event. Once the machine has finished
homing then Mach resumes treating a switch activation as a limit event (ie it Estops) and ignores it as a home switch.

In Machs early days everyone used a parallel port which has only 5 inputs. We all used schemes to combine limits and
homes because we had no choice. With the advent of external motion controllers with much more IO we don't have to
do that anymore. Having said that most people try to combine switches like they used to....and this is to my mind a mistake.

My mini-mill has three separate home switches, each on their own input. Note that it normal to put a home switch at
the end of travel, but you don't have to. My home switches are set about 3mm 'inside' the extreme limit of the axis.
They can in fact be anywhere on the axis. Using the HomeOffset provision of the homing routine will mean that the
machine coordinate 0,0,0 (home) will still be the extreme corner despite the home switches being somewhat inboard.

I personally find that having good quality home switches which result in  repeatable (less than 0.02mm) homing to be
more important than limits.

In the early days of my machine I had a cock-up and I managed to wipe a limit switch off my machine, I hadn't
given any thought as to what would happen if an axis overran. I was so disgusted I took them off. I always meant
to replace them....but have never got around to it, that was six years ago! So I rely on my home switches, which are
good quality and are unaffected by overrun, to do their job and then I rely on SoftLimits. I've had two crashes in
six years. Before I had decent home switches I would bang into limits often.

I am building a new machine and it has 750W AC servos driving the axes. I anticipate that the G0 axis speeds will be
25m/min. So my machine will have to have not just Home switches but Limit switches as well, if I lose control
of this sucker its going to hurt/break bigtime! I am also contmplating whether to use software SlowZone or to have
separate switches. Switches are the most reliable....and I will probably go that way. I will use software SlowZone
initally as a temporary solution.....as you know,.....'there is nothing more permanent than  a temporary solutuion'.

Craig