Messages

5671

Feature Requests / Re: Mach3 Softlimit by dxf

« on: December 15, 2017, 01:47:44 PM »

Hi,
all development of Mach3 has ceased some year ago so this feature will never appear in Mach3 unless someone like you writes code to do it.

Mach4 is the current and developing version but I've seen nothing which matches what you have in mind. I suspect therefore that a feature like one you've
proposed would need to be written by yourself or another user. I doubt that NFS would consider it a viable use of resources given the number of development
tasks that still await them.

I myself use Mach4 and like the flexibility that the modular structure and Lua confer and can think of a couple of programming strategies that might work but
I have no intention to go back to VB, I was never very good at VB to start with.

Craig

5672

General Mach Discussion / Re: Delta servo and uc 300 5 lpt motion controller.

« on: December 15, 2017, 01:20:27 PM »

Hi,
as a preliminary matter there are a couple of things to think about and decide. The drive manual does not tell me the number of pulses the encoder will produce.
I'm going to assume it has a 2500 line (ppr) encoder for 10,000 counts per revolution. 10,000 count per rev is now the entry level standard for differential encoders
while 17bit seems the standard for absolute encoders.

If your servos are capable of 3000 rpm (50 rev/sec) then the encoder will count 50 x 10,000=500k per second. To get maximum resolution would require Mach,
your UC300 and BoB to produce pulses at 500kHz. The specs for the drive input alone say that open collector the input speed max is 200kHz so you will require
differential signalling, ie using two wires rather than just one. This is certainly possible but will markedly increase the difficulty of getting your machine to work.
Sensible decisions about speed and resolution will bring the pulse rate back to 200kHz, ie open collector, and be very much easier to get to work.

You need to decide what you think is a reasonable maximum axis speed which will determine the max rpm of the servo. While it is nice to have full resolution ie
10000 steps per rev, ie 2.6 arc min/step, with a 5mm pitch ballscrew that results in a linear resolution of 0.5um, very good indeed. Can you really use this very
fine resolution, unless you have a hundred thousand dollar plus machine then the answer is probably not. If you decided that a 0.005 mm (5um) resolution is
adequate then the calculation starts to look a lot more achievable.

If you wish to have max speed, ie 3000 rpm (50 rev/sec) at a resolution of 1000 count per rev the numbers are: 50 x1000 =50kHz, easy! In fact you could increase the
resolution and still be comfortably within the open collector limit. Say resolution of 2.5 um, ie 2000 count per rev with a 5mm pitch ballscrew:
50 x 2000 =100kHz. This would be a good compromise.

You may ask how you can vary the resolution of the servo, surely that is fixed by the encoder? That is what 'electronic gearing' is provided for. It allows you to program
your drive so that one step pulse can mean one or more encoder pulses, very convenient and very very crafty, it allows you to use a servo with a built in encoder
to behave as if it had a different encoder fitted if you were replacing an existing device for instance.

Can you post some of the numbers that relate to your machine, ballscrew pitch etc and the specs of the servo you've got, speed and encoder count?

Craig

5673

General Mach Discussion / Re: Delta servo and uc 300 5 lpt motion controller.

« on: December 15, 2017, 12:23:39 PM »

Hi,
well, that's a different kettle of fish altogether.

You need position mode. Forget velocity and torque mode, they don't provide positional motion.

With the exception of the extra enable, fault and fault reset wires the servo drive behaves and is wired the same as a stepper drive.

Craig

5674

Mach4 General Discussion / Re: Powtran PI9000 vfd, need help please.

« on: December 15, 2017, 12:27:15 AM »

Hi,
the page you want to follow is 10.3.2. If you wire per the diagram and get it to work then it should be a simple matter to have either a digital output
or a relay contact of you BoB under control of the ESS which is in turn controlled by Mach in place of the switch and a PWM output of your BoB to
replace the potentiometer.

Craig

5675

General Mach Discussion / Re: Delta servo and uc 300 5 lpt motion controller.

« on: December 14, 2017, 10:47:06 PM »

Hi.
the BoB manual tells us that you have an optpisolated PWM output on pin 17.
Using the UC300 plugin assign Machs PWM output to pin 17 of port 1, which should in turn operate the PWM output
on pin 17 of your BOB. Note that you'll need an isolated 10V supply. For testing purposes you could use a 9V battery
but a mains derived 10Vdc supply would be best. Another alternative is to use a linear reg to drop the 24Vdc auxillary supply
available from the drive to 10V. An LM317, a couple of resistors and capacitors and you'd be fine. Let me know if you need
a sketch of the circuit.

With a modest load on the output pin, say 1-2kOhm you should be able to measure a voltage corresponding to spindle speed
by issuing S*********x commands at Machs MDI line. If you can do this you are well on your way to effective speed control of
your spindle.

Craig

5676

Mach4 General Discussion / Re: Powtran PI9000 vfd, need help please.

« on: December 14, 2017, 05:46:48 AM »

Hi,
so I guess its what you want rather than what you need.

I suggest to start with just have Mach turn it on and off with speed set by the VFD control panel. Once you've got that happening program the VFD to accept
a voltage input and use a potentiometer to provide the voltage. Once your happy with that then use  PWM output to supply the control voltage.

Craig

5677

Mach4 General Discussion / Re: Powtran PI9000 vfd, need help please.

« on: December 14, 2017, 04:55:26 AM »

Hi,
have you got the VFD hooked to your motor? Can you control the motor (stop/start/speed) from the VFD control panel?

Craig

5678

Mach4 General Discussion / Re: Powtran PI9000 vfd, need help please.

« on: December 14, 2017, 04:48:16 AM »

Hi,
constant surface speed requires infinitely variable speed control. Is that what you want or what you need?

Craig

5679

General Mach Discussion / Re: Delta servo and uc 300 5 lpt motion controller.

« on: December 14, 2017, 04:30:39 AM »

Hi,
no, you don't have to use position control. Position control is very precise and good for threading but even for threading you can use just speed control.

I suggest then that you concentrate on velocity mode control. Once your familiar with that some of the other strategies will make sense but for most of the
time velocity control will be good for what you want to do.

You will need to program the drive to accept an analogue voltage as a velocity control input.

You will also need the UC300 and BoB to produce an analogue voltage from PWM.

There will probably be two (at least) other control signals between the UC300/BoB and drive, an enable signal to the drive , a fault signal from the drive
to the BoB/UC300 and possibly a fault reset line as well.

What BoB have you attached to the UC300? Can you post the manuals?

Craig

5680

General Mach Discussion / Re: Z axis loss of cutting depth after multiple Z movements

« on: December 14, 2017, 03:25:50 AM »

Hi,
even if you buy an Ethernet or a USB external controller like the ESS or the NVEM you'll still need your G540, it has your stepper drivers in it.
External motion controllers do not drive motors themselves.

The cheapest external controllers are the UC100 (don't buy a Chinese knockoff one from EBay) or  the PMDX-411. They are equivalent to one parallel port
and plug into USB on your PC. You could plug you G540 straight into it.

I use an Ethernet Smooth Stepper and have no problems recommending them, the equivalent of three parallel ports. PoKeys, PMDX and CNCDrive do good value
boards, all probably about the same price as the ESS.

While I understand you wishing to buy cheaply I think buying cheap Chinese is a mistake. That is probably a pretty contentious opinion but if you spend a few hours
reading on this forum you will see dozens if not hundreds of complaints about cheap Chinese gear. The evidence is pretty plain.

Craig