2.5 Axis Direction Control

[ee_cnc]

Hi,

I've got a 2.5 axis PCB engraving table. The Z-axis is controlled by a solenoid and the X and Y axes are controlled by stepper motors. I'd like to use the Z-axis direction pin to control the up/down motion of the solenoid. In the standard stepper configuration, the Z-axis direction always returns to a logic zero when the stepping is completed. Does anyone know of a way to make the direction "stick" after the stepping is completed?

Thanks in advance.

[Horsedorf]

Okay, I take it this is one you are building and not one you've bought.

Since the direction last seen when a step was taken is the 'real' current direction, you might use a bit of logic circuitry to make the direction bit 'stick'.. I think, using a Type D flip flop with the step connected to the 'clock' line and the direction connected to the 'input' line would do it, and use the 'd' output line to drive the solenoid.

Natch, you are going to need some stuff along with that, like.. a logicl level mosfet for controlling the current to the solenoid, and perhaps some transistors to help buffer the inputs, or maybe just 5 volt zeners to clamp the inputs to logic levels might do it.

Good luck.

[samco]

Look at emc2's hal layer. I bet you could do it pretty easy in that.

Do you need to use z? could it be an M code? one for up - one for down?

Either way - it should be pretty easy to do.

sam