[Precent]

Hi, I just have a quick question about setting up the step / direction interface from EMC to my Viper drives. Since EMC allows you to choose which output each parallel port pin is used for, could I just wire up a 25 pin connector like show below and run each Viper drive from my computers parallel port? Since the Viper step / direction interface is opto-isolated on the board, is there any reason to use a separate breakout board? Thanks.

1
2 - X Step
3 - X Direction
4 - Y Step
5 - Y Direction
6 - Z Step
7 - Z Direction
8
9
10
11
12
13

14
15
16
17
18 - X Step (ground)
19 - X Direction (ground)
20 - Y Step (ground)
21 - Y Direction (ground)
22 - Z Step (ground)
23 - Z Direction (ground)
24
25

[Larken]

You should use a BOB to buffer the signals and noise filter inputs.

The Step/dir inputs on the viper don't use a ground signal. They need a +5v on the 2 middle pins then the outer (step and direction pins) are pulled low by the driver chip in the printer port.
You can get the 5V off a USB connector

Look at the diagram in the manual again. See there are no ground connections.

Don't forget you should hook up the Fault output from the Vipers to signal EMC to stop if there is a fault.
A BOB is $23 at pc4cnc


Larry