Centroid Community CNC Support Forum

Today I removed the Acorn Control box from my mill and replaced it with a full featured Acorn Six :

RS422 Differential Drive Output and Scout Expansion Interface Board
SCOUT Encoder Expansion Kit
WMPG6
Ultimate Plus license

My goal is to make the mill 5 Axis with full closed loop since RS422 scales with a DRO are already on the machine
I also will install ZRI home with index pulse from the scales/encoders on rotary axis
A and C axis will be driven with A6 Servos, XYZ with the old steppers CL57T and CL86T drivers V3
All Step/Dir RS422 differential

I started with a new cabinet, Acorn Six ready installed in bench test mode ( that was done after work the last few days ) :
Ripped off the old cabinet, removed the drivers for XYZ and the spindle servo driver and stuffed the parts in the new cabinet.
A few hours later, XYZ is running, the machine is homing and the spindle is working with -10/+10V
Spindle Servo is wired now without SSR, only -+10V / VFD Enable / Spindle OK Just 6 wires to solder to the CN1 connector

Tomorrow I will wire and configure the new servos for A and C axis and swap the servo for the already installed stepper on my A axis
If this is working in a short time, I will also wire the scales to the scout expansion.

Issues I had to solve today:

no action on the CL57T drivers
Used inversion of the quadrature signal by software:
Steppers moving but needed to be set up to 1000 pulse while the software is at 4000 pulse to move 1mm if the software commands 1mm
CL86T is running like a bag of seashells.

Solution:
uncheck inversion and swap A /A and B /B on the CL57T drivers, CL86T can be wired as it should be
Now the steppers are running as smooth as before.

I am not sure if it is a bug with the drivers, or in the software if inversion is selected

One thing I am not sure at is if Acorn Six can do full closed loop on a rotary axis....

... anyway easy peasy and fast to set up a new Centroid CNC


Uwe

Today I wired the stuff controlled with the outputs and got the first A6 servo running.
Wasted lot of time to get it working figuring out how it runs with the RS422 signals.
Solution was to invert Quadrature in the Wizard, in this case it works, so I think the issue yesterday was from the CL drivers not from Centroid.
Also setting the step rate in the driver did not work, till I figured out that the servo must not be enabled to change this setting...

Changing the stepper to the A6 on my 4th axis was also not a simple bolt on, the adapter needed to be machined, but now the 4th axis is faster and almost noiseless.

Issue today:

I set up my laser to PWM2 but without second spindle enabled no PWM output, with second spindle enabled PWM is on a low level and not changing it also is not going off with S0 but set up to be off at <S5

Report is attached.

Uwe

Settings and wiring of the A6 Servo so far. Drive OK is working in series with the other drivers. I made ZRI Home with the differential PZO- and PZO+ outputs because I could not make the OZC Output to trigger an Input,
maybe someone here has a better idea...
Anyway home on the Vertex is within 0.01 degree. Maybe I will get a cable with battery for the absolute encoder and use the home feature in the A6 driver.

Uwe

suntravel wrote: ↑Sun Jan 12, 2025 11:13 am Today I wired the stuff controlled with the outputs and got the first A6 servo running.
Wasted lot of time to get it working figuring out how it runs with the RS422 signals.
Solution was to invert Quadrature in the Wizard, in this case it works, so I think the issue yesterday was from the CL drivers not from Centroid.
Also setting the step rate in the driver did not work, till I figured out that the servo must not be enabled to change this setting...

Changing the stepper to the A6 on my 4th axis was also not a simple bolt on, the adapter needed to be machined, but now the 4th axis is faster and almost noiseless.

Issue today:

I set up my laser to PWM2 but without second spindle enabled no PWM output, with second spindle enabled PWM is on a low level and not changing it also is not going off with S0 but set up to be off at <S5

Report is attached.

Uwe

chris just made improvements in this area for acornsix and pwm2. will be in v5.24, should have a beta soon.
pwm2 will only turn on with the M37 (laser on) .
Note G37 (Laser velocity modulation) only works with PWM2 not PWM1, (PWM1 is for spindles, PWM2 is for Lasers)

Great news. Yes I know M37 laser on M38 off. That worked only with the second spindle enabled.
If the second spindle is enabled the field for PWM base frequency is greyed out in the wizard, but can be set in the parameters.

Uwe

i know you know just commenting mostly for others that are reading.

Now the steps are getting smaller....

Made a better wiring for the A Axis servo with ZRI Home and did some quick and dirty testing with the NPN Sensor only taped on the rotary

I am very pleased with the result, measured at 155mm diameter it repeats within 0.002mm after swinging a second +-0.008mm.

The servo is out of the box, no autotuning or manual tuning so far, and there are lots of options, even to dial in the friction of the assembly which is for sure on the high end with a worm gear and almost no roller bearings in the rotary.

This dirt-cheap servo can also do full closed loop with an external scale or rotary encoder, cool option for Acorn to use scales.

Hard stop home with following ZRI is also a option.

Uwe

How exactly do you have the ZRI Home wired now?
Where you able to get the OCZ output to work or are you still using the F5305S?

Centroid_Tech2 wrote: ↑Wed Jan 15, 2025 1:46 pm How exactly do you have the ZRI Home wired now?
Where you able to get the OCZ output to work or are you still using the F5305S?

I am using Z /Z with the F5305S

I could not get the OCZ to switch an input. I have tried to set it positive and negative Inputs set to NPN and PNP none of the combinations did something. Inputs are always on or off.

Uwe

C-Axis Servo is also online, well kind off. If both A6 divers are enabled the lights are going out, because the RCCB is switching off

Both alone are ok, I must get an RCCB type B with more than 30mA

Temporarily I got the power for the second driver from another circuit with another RCCB.

I could eliminate the overshooting and swinging with the autotune function to mesure the inertia load and set some parameters by hand.

Uwe