Monday, November 3, 2008

Fixed cycle counting


It's been awhile since i have worked on the spot welder controller. I sat down tonight to fix the cycle counter hardware. I originally used two diodes and a resistor divider. This worked but it also added a great deal of phase shift to the signal. I replaced the diodes and resistor divider with a 100K resistor. After looking more closely at the attiny2313 data sheet i was reminded that the device has integrated clamping diodes. So i can simply use a voltage reference to fetch the signal as the diodes will clamp .5 on either side of the wave in respect to the supply. I also added a section that allows the adjustment of power cycles for the manual section of the controller.

The picture above is a screen shot of the fixed cycle counter and phase relationships. At this point i am ready to test the controller. I don't have time to test it right now so i hope to get that done tomorrow. I will probably test the controller as is on the bread board though i should build a complete board.