Thanks Derek, I think you're probably right. I'm going to give Arturo another shout, but I don't think I'm going to be able to use his PWM solution. First of all, I just can't live with 1200 RPM demand sitting there all the time....that's not safe. And secondly, the spec says 0-10vdc, not .5-10vdc. I love everything else about the C11gs. I've been looking at the Homann DC05 I think it is. The manual on his site isn't much better than the Chinese VFD manuals for content, and accuracy. Kind of hard to follow the setup and testing, but at least from what I've read, the specs are solid. That's what counts. Besides, the Huanyang VFD,s can be set to ignore up to 10Hz starting demand which is about .25vdc on the 0-10vdc scaling. That would be a nice solution, if Arturo could get it below that level. I'll see. I assume Homann's is already well below that, from what I've read.
Ozzie