Tom,
The +5VDC is the "return line" for the STEP and DIRECTION inputs. The way it works is current (16mA) flows from your PC +5VDC thru the STEP opto LED, back to your parallel which completes the path when your STEP output goes low. Same goes for DIRECTION.
The +5VDC doesn't power anything in the drive.
Mariss Freimanis
Geckodrive Inc. |