servo

so where do I ground it?

It is connected to the same ground, more or less. The command ground is connected directly to the negative lead on the power supply, and the regulator is connected to the negative bus on the board, which is then connected to the negative lead on the power supply.

I'll attach a picture of my setup. Hopefully it helps. This is the first circuit I've ever designed.

Hey, all. I've run into a real problem with my control circuit. The circuit is simple enough. I am designing a controller for a servovalve that looks something like this. It's a 10VDC signal with negligible current. The equipment can handle a couple of extra volts, so the 12VDC won't hurt anything. The frustrating thing is, it works in one direction, but when I flip the switch to reverse the direction of the command, it stops working unless I turn the pot all the way and then I get a large current draw. I don't understand at all why this is happening. Why does it work in one direction, but not the other? When I hook up a power supply directly to the switch, it works fine, but with the regulator and pot in there it starts acting funny. Help please! I've been stumped for two days and I need to get this figured out. I should say that I forgot to ground the regulator in the schematic. It is grounded on the breadboard, though. Also, I've run it through Multisim and it works just as it should, so does that just mean there's a problem with the way I have it set up on the board?