Messages

4311

General Mach Discussion / Re: Z axis rapid speed control

« on: June 13, 2018, 12:49:37 AM »

Hi,
can you tell us a bit more about your machine?

What size and spec are the steppers?
What are the drivers?
What is the voltage of the stepper supply?
What current setting have you applied to your drivers?
What microstepping regime are you using?
What is the pitch of the lead screws?
Is there any belt/gear reduction between the stepper and the lead screw?
What are the steps per unit values in the motor tuning pages?
What controller (parallel port/external) are you using?

Craig

4312

General Mach Discussion / Re: Z axis rapid speed control

« on: June 13, 2018, 12:43:27 AM »

Hi,
keep turning the velocity down, velocity and acceleration are almost always the culprits when a stepper
loses steps. Keep turning it down until you find a sweet spot where it behaves. Then you have to ask the
question 'is this right...or is there another underlying fault?'. You will not be able to answer that question
until you have established that there is indeed parameters (velocity, acceleration) for which the stepper does behave.

Craig

4313

General Mach Discussion / Re: VFD HELP

« on: June 12, 2018, 11:25:11 PM »

Hi,
try both, but I think either will be fine, they will differ only by the slip, typically only a few
percent.

Craig

4314

General Mach Discussion / Re: VFD HELP

« on: June 12, 2018, 10:42:11 PM »

Hi,
that is probably a good explanation. May I suggest have the VFD display frequency, that means
revs per second for a two pole motor.

Freq=400 Hz or 400 rev per second = 24000 rpm.

Craig

4315

Mach4 General Discussion / Re: Mach 4 Spindle Speed Control

« on: June 12, 2018, 06:28:37 PM »

Hi,
an index pulser is a device attached to the spindle to generate a signal each time the rotor turns. If you don't
know what it is...you don't have one. Uncheck PID, you are not able to use it.

Craig

4316

Third party software and hardware support forums. / Re: Ethernet smoothstepper and touch plate setup issues.

« on: June 12, 2018, 05:24:42 PM »

Hi,
I think I would measure the input resistance of the input and try to work out why it differs
so wildly from the representitive circuit diagram in the manual.

With the Bob powered, with multimeter put the red lead to the input having previously dissconnected your
probe, and the black lead to earth. Is there any voltage at the input? Note if there is voltage on the pin that would indicate
that the buffer IC has failed.

With the BoB unpowered what is the resistance?

Craig

4317

Third party software and hardware support forums. / Re: Ethernet smoothstepper and touch plate setup issues.

« on: June 12, 2018, 05:10:21 PM »

Hi,
50mA is I believe too much and there is a risk that there is a fault or some misapplication happening
and failure may result.

Craig

4318

Mach4 General Discussion / Re: Mach 4 Spindle Speed Control

« on: June 12, 2018, 03:17:40 PM »

Hi,
you don't say if you have an spindle index signal?

If not the PID wont work. The PID procedure needs a way of measuring the actual current spindle speed and without an index signal it can't do it.
In absence of proper feedback I would expect the closed loop controller, aka the PID, to be either max, ie 24000 rpm or under slightly different circumstances
minimum, I suspect in your case the VFD is programmed to 3500 rpm min.
Uncheck the PID setting and the PWM and spindle will perform  open loop. You might reasonably expect accuracy of 5-10%.

Craig

4319

General Mach Discussion / Re: Feed rate speed error

« on: June 12, 2018, 03:04:08 PM »

Hi,
can you confirm the accuracy of your steps per unit values by issuing this MDI:

G0 X0
X300

Does the X axis move 300mm?

Craig

4320

General Mach Discussion / Re: Z axis rapid speed control

« on: June 12, 2018, 12:02:01 PM »

Hi,
no.

A G0 move is made at the maximum velocity of that axis...aka the motor tuning velocity
A G1 move is made at the prevailing F speed up to the maximum velocity of the axis, ie the G0 rate.

Craig