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  • RotarySMP
  • RotarySMP's Avatar
18 May 2026 09:43 - 18 May 2026 09:47
Replied by RotarySMP on topic Schaublin 125-CNC retrofit.

Schaublin 125-CNC retrofit.

Category: Turning

Thanks for your ideas, this all really helps. 

This is a summary of the various ways I could add sensors, or control to the overall gear ratio. 

1/ pull the motor fan, and use the shaft stud to drive an encoder, and then mount an electric cooling fan on the shround for the motor.
++ Seems most robust solution.
++ covers entire drive train with single unit.
++ high resolution, low noise
++ encoder in and encoder out, the gear ratio would be rock steady and real time.
++ does not require pulling the entire drive unit. 
++ spare encoder input available on 7i85

2/ Make a little amplifier to scale that 0-10V motor speed output to 0-36V
++ Simplest solution
-- I am not strong in electronics.
-- less resolution than motor encoder
-- lower qualiy signal than encoder

3/ use an optical or hall sensor to count motor fan fins, or CVT features.
++ Slightly simpler that adding an encoder... or not...
-- as it would need the entire drive pulled.
-- less resolution then encoder
-- doesn't sense gearbox ratio.
-- dirty environment, unsuitable for optical sensors.

4/ Add an encoder to the CVT linkage, or to the CVT lead screw.
-- better options above
-- need to pull drive unit.
-- non-linear relationship to ratio
-- needs LUT or algorythm to convert to approx ratio.
-- less resolution than motor encoder
-- doesn't sense gearbox ratio.

5/ Replace the CVT motor with a stepper or servo
-- more work than the better options above
-- large wiring change, add addition servo driver etc
 -- need to pull drive unit.
-- non-linear relationship to ratio
-- needs LUT or algorythm to convert to approx ratio.
-- less resolution than motor encoder
-- doesn't sense gearbox ratio.

6/ Use a laser range finder on the CVT belt with a look up table to estimate ratio.
-- dirty environment, optics will likely unreliable over time.
-- better options above
-- non-linear relationship to ratio
-- needs LUT or algorythm to convert to approx ratio.
-- less resolution than motor encoder
-- doesn't sense gearbox ratio.

7/ Using a sensor to detect backgear lever position .
-- dont think there is an external lever, it is internally, pneumatically actuated with no external moving parts.
-- Since it is only shifted stationary, this is the easiest to infer. I can log last position, and cross sheck it using overall ratio, so this seems unnecessary.

8/ adding a gear tooth detector in the gearbox
-- significant effort to pull, disassemble drive unit, and drill hole in housing, design and mount sensor
-- less resolution than motor encoder
-- better options above

Seems to me that the motor encoder would to be the most likely to simply work, and work best. It covers the entire drive train in a single component, offers the highest resolution, and provides (with the spindle encoder) the most direct measurement of overall reduction ratio without noise, interpolation, LUTs etc.

However, before I add a sensor which Schaublin didn't need when they designed this system in the first place, I am thinking of taking one last swing a software solution. My original idea, which I have not yet tried. How accurate does a lathes spindle speed control really need to be?

- divide the CVT range into 5 "fixed ratios", one second apart.
- survey the whole range, generate a look up table of CVT "fixed ratio", and VFD Hz.
- Command the CVT in one second bumps (gear changes).
- largely open loop with VFD frequency interpolated between LUT values.
- Maybe switch to closed loop to fine tune speed (but I am hoping not to need to)
-- if closed loop needed, add PI gains to the LUT.
--  I already have VFD "motor on speed" wired in, and had not thought to use that to gate and freeze the ratio calculation when it would be garbage.
-- when there is steady state operation, use the calculated ratio just to cross check and maybe correct for CVT drift after multiple shifts. In practice, I expect it to be on limits quite often, which is a natural drift reset.

If I can't get that working, and really do need a sensor, I tend to the motor encoder.

 
  • MiMaMoadlo
  • MiMaMoadlo
18 May 2026 07:15

No unhoming after emergency-stop or limit-sw trigger

Category: General LinuxCNC Questions

Thanks, I will look into these parameters!

My thought behind adding it as an E-stop was to have it as part of the safety relay circuit outside of linuxcnc.
  • Buzzcut
  • Buzzcut
18 May 2026 02:24

Probe screen V2 with Gmoccapy T/M6 causes system to pause - Solved+Corrections

Category: General LinuxCNC Questions

I need help with this. I can not seem to get mine working. If you remember how you where able to do it would be a great help. The hal file only loads after the psng probe screen. I can switch back to the gmoccapy change.ngc and it work as expected but i can then not probe like i want to. I can not get the correct tool height after gcode start. Any help would greatly be appreciated!
  • tommylight
  • tommylight's Avatar
18 May 2026 00:25
Replied by tommylight on topic Mill Retrofit with Fanuc DC Drives

Mill Retrofit with Fanuc DC Drives

Category: HAL

Measure between gnd and each channel.
  • PCW
  • PCW's Avatar
18 May 2026 00:24 - 18 May 2026 00:27
Replied by PCW on topic Mill Retrofit with Fanuc DC Drives

Mill Retrofit with Fanuc DC Drives

Category: HAL

You cannot do this without two  differential probes.

Measure the A,B signals relative to ground.

But as you said I don't think this is the issue as long as the position
readout is correct.
 
  • tbrasselle
  • tbrasselle
18 May 2026 00:03
Replied by tbrasselle on topic Mill Retrofit with Fanuc DC Drives

Mill Retrofit with Fanuc DC Drives

Category: HAL

I was measuring it against the compliment. I had the probe on channel A and the ground on the probe clamped to the inverse channel A. Same thing for channel B.

Viewing channel a and channel b in HALSCOPE everything looks normal. So I’d assume this isn’t actually the issue either.
  • HansU
  • HansU's Avatar
17 May 2026 19:27
Replied by HansU on topic Launching gladevcp panel with gmoccapy

Launching gladevcp panel with gmoccapy

Category: Gmoccapy

The GMOCCAPY documentation indicates that if no EMBED_LOCATION is defined, the the glade VCP will be floating. Is that no longer valid?


AFAIK this was never supported. Where do you have this info from? I can't find such in the current Gmoccapy documentation.
  • tommylight
  • tommylight's Avatar
17 May 2026 18:46
  • agant172
  • agant172
17 May 2026 18:31

Mesa conversion for a Mazak VQC 20/40 M2 mill

Category: Driver Boards

Hi all,
Hoping this is the right place for a conversation about machine controller conversions. I'm a hobby user, not a production shop. I've got a  Mazak VQC 20/40 mill with M2 control, it's a nice fully functional machine with good tolerances for it advanced age. It's lack of memory is a real pain point. Programming in Mazatrol CAM M2 was probably great back in the day, not so much now. I can send G-Code files to it, but hit file size limits rather quickly. It's not capable of drip feed. I think I'm ready to go for the Mesa upgrade. With AI help I've input all the info I can think of, this is where I'm at... realistic? reasonable?

Servo Motors & Drives:
X-axis: Mitsubishi HD-81-12 DC permanent magnet servo motor with analog drive accepting ±10V command (terminals: AX, BX, G1X, G2X, G)
Y-axis: Mitsubishi HD-81-12S DC PM servo with analog drive (terminals: AY, BY, G1Y, G2Y, G)
Z-axis: Mitsubishi HD-101-12 DC PM servo with analog drive (terminals: AZ, BZ, G1Z, G2Z, G)
All three drives are MELDA-8 or similar Mitsubishi analog cards that accept ±10V command signals—these are REUSABLE
Position Feedback:
X-axis: Magnescale SR-921RH linear encoder (outputs quadrature signals directly) + MS3100B 20-29P tacho generator
Y-axis: Tamagawa Seiki resolver (MS3108B 20-29P, pins: RS1, RS2, RC1, RC2, RO1, RO2) + tacho generator
Z-axis: Magnescale SR-921RH-450-R-0 linear encoder + MS3108B 20-29P tacho generator
Spindle:
Mitsubishi AC motor SE-EV-FV with FREQROL FR-SX VFD controller
Already accepts 0-10V analog speed command and direction signal—fully LinuxCNC compatible
Tool Changer:
20-tool carousel ATC with CAT40 tooling
Nachi proximity sensors for position detectionMesa Hardware StackCore Cards 
7i92H  - Ethernet-based motion controller, main brain
7i77  - 6-axis ±10V analog outputs + encoder inputs + 48 I/O points
7i49 - 6-channel resolver interface (for Y-axis only)
7i73 - Pendant/operator panel interface

Servo Drive Connections:

Existing 24VDC power supply (HR-11F, outputs P24 and G24) remains in service:
Mesa 7i77 I/O is 24V compatible
Existing Contactors (3S-1, 3S-2, 3S-3, 3S-4):
Control servo drive enable sequencing
Spindle power control
Lube/coolant pump control
These stay and get controlled through Mesa 7i77 I/O outputsATC IntegrationInputs to LinuxCNC:
Tool-in-position sensors (Nachi proximity switches)
Carousel rotation feedback
Gripper open/close confirmation
Drawbar clamp/unclamp sensors
Outputs from LinuxCNC:
Carousel motor control (forward/reverse)
Gripper solenoid
Drawbar solenoid
Air blast control
  • andrax
  • andrax's Avatar
17 May 2026 16:43
Replied by andrax on topic Tuning Steperonline A6 Servos

Tuning Steperonline A6 Servos

Category: EtherCAT

Oh, I almost forgot – I wanted to let you know if I succeed.I’ve been gradually increasing the C00.05 stiffness parameter.
  • PCW
  • PCW's Avatar
17 May 2026 16:42 - 17 May 2026 16:43
Replied by PCW on topic Mill Retrofit with Fanuc DC Drives

Mill Retrofit with Fanuc DC Drives

Category: HAL

Are you measuring the encoder signals against ground?

(you cannot measure differential signals on an oscilloscope  without a differential probe)
  • Szymik
  • Szymik
17 May 2026 15:41
Replied by Szymik on topic Spindle configuration

Spindle configuration

Category: StepConf Wizard

Unfortunately HDD is dead. A colegue of mine will bring a laptop he was using with simillar machine but on Windows+Mach setup, maybe i will get some info from there
  • PCW
  • PCW's Avatar
17 May 2026 14:29

7i76D Spindle Analog output changed overnight!

Category: Driver Boards

I guess the H11L1SM optocoupler could be damaged but that's
much less likely as it does not connect to the outside world.
  • Okojo
  • Okojo
17 May 2026 14:28

rs274ngc as a standalone interpreter — driving grblHAL over UART, no HAL, no RT

Category: General LinuxCNC Questions

I wanted to share an approach that may interest anyone running CNC on a Linux SBC without a Mesa card or a real-time kernel.

### The setup

Hardware: Arduino UNO Q — a single board that combines a Qualcomm QRB2210 (Debian 13 Linux) with an STM32U585 MCU connected via an internal UART (`ttyHS1`). The STM32 runs grblHAL and handles all real-time step generation. The QRB2210 handles G-code interpretation.

### The key insight

`linuxcnc-uspace` ships a Python API for `rs274ngc` that works perfectly outside of a running LinuxCNC instance:

```python
import gcode
from rs274.interpret import Translated, StatMixin

result, seq = gcode.parse(filename, canon, "G21", "")
```

This gives you the full rs274ngc interpreter — canned cycles (G81, G83…), O-word subroutines, G92/G5x coordinate systems, polar coordinates, error checking — with zero HAL setup and no real-time kernel requirement.

The `canon` object intercepts the resulting primitive motion calls (`straight_feed`, `arc_feed`, `spindle_on`…) and translates them to grblHAL commands streamed over serial with `ok`-based flow control.

### What rs274ngc handles automatically

- Canned cycles expanded to primitive G0/G1 moves
- Incremental → absolute coordinate conversion
- G5x / G92 work coordinate offsets
- Polar coordinates
- O-word loops and subroutines
- Unit conversion (G20/G21)

### Architecture

```
G-code file
    ↓ gcode.parse() — rs274ngc Python API
canon calls (straight_feed, arc_feed …)
    ↓ Python bridge
G0 / G1 / G2 / G3 over /dev/ttyHS1
    ↓
grblHAL on STM32U585 — real-time step generation
    ↓
Stepper drivers / CNC shield
```

Note: rs274ngc canon calls are always in inches (internal unit). All coordinates are multiplied by 25.4 before sending to grblHAL in mm mode.

### Repos

- Bridge (Python, runs on QRB2210): github.com/hoshigarasu/canon-grbl-bridge
- grblHAL firmware (STM32U585 port): github.com/hoshigarasu/grblHAL-STM32U585

Demo video: XY pen plotter drawing a 50mm circle, G-code interpreted by rs274ngc on the QRB2210, executed by grblHAL on the STM32U585. [photos.app.goo.gl/vnDY3CgpnHprdv5dA]

Happy to answer questions about the rs274ngc Python API or the canon interface.
  • Yippiekae
  • Yippiekae
17 May 2026 12:52
Replied by Yippiekae on topic Tuning Steperonline A6 Servos

Tuning Steperonline A6 Servos

Category: EtherCAT

I'm at this step to. But I feel like it's been worse after the autotune than it was before.
That software is such a mess that I regret not going the Leadshine way.
I also have a slightly noisy Z axis servo but I can't find the gain parameter... Any clue ?
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