Quote Originally Posted by Neale View Post
Clive's comments are very valid, especially as this is a somewhat random problem.

Couple of points to make, though.

There are a few parameters in the VFD that control how it drives the spindle. From memory, on my own VFD, these are something like sensorless torque control and V/F. These change the way that the VFD generates its output, and also senses how the spindle is reacting. I'm really not an expert on these and which the best choice is. What I can say is that you seem to be accelerating the spindle quite quickly. This might be OK for your spindle, but perhaps someone else can listen to the video clip and comment?

Second point is to ask if you can show the parameters that DI1/DI2 are set to. They are probably correct, but it would be good to check. You say that you have set your VFD to 2C mode, which is what I would also do. However, you appear to always enable output 4 to start the spindle, and then enable output 3 for reverse. However, in 2C (2-wire) mode, you should use output 4 for forwards, and output 3 for reverse. Never use 3 and 4 together. This might explain the problem and random starting direction in reverse - depending on whether the BOB sets 3 slightly before or slightly after 4, the VFD could start in forwards or reverse. Make sure that the DI pins are correctly set (one for F, one for R) and configure UCCNC and the UC300 to use one or the other output in conjunction with the analogue signal. Might be the source of at least one of your problems!

Thank you Neale,

The sensorless parameter in VFD is "Ctt [Motor control type] - uuC (Sensorless vector control)", in last configuration I tried to use "Ctt [Motor control type] - set to Std (Standard motor)". But will make a change and will come back with results :)

DI1 and DI2 is set to be Forward and reverse inputs, I will double check if there is anything to configure further, once I will be back from work.

Very good eye Neale on noticing output activation - fantastic :) that explains why in some case spindle rotation dir is unpredictable :). Thing is that I can't have separate pin output for FWD / REV as in UCCNC, if PWM spindle control mode is selected - only PWM control pin and DIR pin are available to set (can't choose FWD / REV pins). Maybe I should go with relay control for FWD / REV functions, in that case, two separate PIN's can be chosen.

Will tryout and will be back with results :)

Thanx ! :)