Analog 0-10v control using encoder

[centroidmax]

Hi all,

I just got my first Acorn board installed in a modified ShopFox mini lathe.
I have a speed governor (0-10v to DC110) installed as the drive to the existing motor.
This seams to work ok, except I am not getting accurate RPM on the spindle (ex: 950 when requesting M3S1000, 1480 when requesting M3S1500, etc..).
I have an 'OMRON' encoder from china model E6B2-CWZ1X (8000 pulses in CNC12) geared 1:1 with the spindle. The single turn count looks right if I manually turn the spindle 1 rotation.

I am looking for the option to actively compensate the 0-10v analog out based on the readings from the encoder.

Thanks!
Maxime

[tblough]

Here's how to set up Acorn for rigid tapping: https://www.centroidcnc.com/dealersuppo ... ds/304.pdf

It will show how to tune your VFD. Spindle speed control is open-loop and does not use the encoder to adjust speed. The encoder is used only to read the actual spindle speed and adjust the Z-axis motion to match during tapping operations.

Depending on your VFD, you should be able to tune speed within 0.5% or so. You will be limited if your vfd does not have span and offset settings. However, someone recently posted on how to modify the PLC program to incorporate span and offset adjustment in the DAC calculation for the spindle if your VFD is not capable.

[centroidmax]

Thanks,
Yes I understand that the primary function (only function?) of the encoder is a feedback for threading / rigid taping.
I should be able to fine tune the min V and max V to adjust the speed a little better, but this will not work as good as a closed loop system.

I such a feature planned? Doable in the configuration files (like adding a constant feedback loop in the config file that translates the S value to volt value)

Thanks

[Taifeng]

The system controller (MCU) output PWM is converted to 0-5V or 0-10V voltage output by GP8101 after optocoupler isolation. 2. The 0-5V/0-10V voltage is converted into PWM signal by GP9303, and then input to the inverter or motor driver for motor speed regulation after optocoupler isolation.