Hi,
I have a chinese variable frequency driver for my spindle. It provides a 10V supply and takes a 0-10V input voltage for spindle speed. I want to integrate this with my GCODE interpreter so that I can control machine speed from GCODE. This means a level change from the digital voltage level and I want to use opto isolation to protect the controller chip.
Output will be a PWM signal which needs a low pass filter after the FOD817B opto isolator .
I have a circuit but just realised that it has different charge and discharge resistance which means the output voltage will not correctly reflect the PWM ratio.
Can someone suggest a better way of doing this?
Thanks.
[EDIT] Ah, I've just realised that if I increase the filter resistor to 100k, the difference becomes unimportant. Does this look like a valid way to drive VFD?