Quote Originally Posted by Nr1madman View Post
Okey..
Read on cncdrive forum about similar problem and it turned out that it was interference from switches that caused it. Strange when the e stop was set to port and pin 0!

If it continues to work for me I need another solution for vfd control! Is rs485 to usb twowire system ok?
But that only let's you control speed and not start/stop from system? Or am I mistaken? :D

You can control the forward/reverse control, as well as spindle speed, over the serial bus - I do that now with Mach3, using the HuanYang controller plugin. Clearly depends somewhat on your controller (being a HuanYang) and the plug-in for UCCNC (I've not tried it, but it seems pretty basic functionality - I've got the code for the LinuxCNC driver and it's just a different control sequence that gets sent).

USB interface?, it's fine using that for a USB->Serial convertor - there's nothing time critical sent over this interface if all you're doing is controlling spindle speed etc (standard chinese AC spindle, etc). Just use a decent twisted-pair cable to connect the interface to the spindle inverter. (also, I can't remember WHAT connector I used - but I found it easier to fit a 2-pin connector into the side-wall of the inverter to allow the modbus interface to be easily made/unmade (my frequent changes to the control box solution made me want some flexibility between modbus and discrete control).