When performing the first "actual" cuts on my new 12x16 running Mach-3, I saw that the Z-axis was loosing steps. The X & Y axes appeared to be ok. Initially I wasn't sure if I was making too heavy a cut causing the problem, so I tried some adjustments, but the problem remained. At that point I went back through the configuration steps starting with Ports/Pins. At the bottom of that dialog, I noticed that the Kernel Speed was set to 45,000HZ.
In the few days of waiting after I ordered my Zenbot until it arrived, I had installed Mach-3, run the Driver Test program and found that my PC (although 25, 35 & 45,000HZ all tested at 'excellent' level) seemed to work best at 25000HZ, and set it for that. How did it get changed? I set the Kernel Speed back at 25,000HZ, and re-tested the driver, which confirmed the most stable operation at the 25 speed. After that, I re-ran my cuts and confirmed that steps were no longer being lost.
By experimentation I discovered that the Kernel Speed selected from the Ports/Pins dialog is SAVED in the machine configuration file, specifically zenbot.xml. What happened was that Shaun sent me a new copy of the configuration file when he shipped the Zenbot, which I used during my subsequent tests and configuration settings. It's not his fault! He was doing me a favor in providing the "latest" version. Anyhow, I didn't notice the speed change and didn't realize that the "Driver Test" needed to be re-run to keep things in sync.
My controler PC is a 2.00GHZ Intel Celeron, with 1GB RAM, Matrox 32MB video, running Win-2k. It may be that it "will" run without loosing steps set to 45,000HZ, if I simply set it to that and re-run the Driver Test program at that speed. For now, the Zenbot is working smoothly and reliably ...and I am having too much fun to experiment with it more right now. I'll be posting some photos of the first successful projects later on.
Anyone with with additional information or insight on this topic, I hope you will share your thoughts.