Usefulness of the Opto-Isolation in Breakout Board

[leaveme]

Hi

I'm sorry for repeation of my query. But someone may speak from his experience and expertise on Opto-isolation.

I would like to know, what is the impact if I disable opto-isolation in the BOB part of the Stepper driver? Can it damage driver chip if I make a direct connection to the PC? Or, in the other way, can it damage LPT port in PC?

Please visit the following thread I you feel more interest about my query.
http://www.cnczone.com/forums/showth...=110986&page=4

[Al_The_Man]

I can't speak directly to that particular BOB as I have never used it, but it is my custom with PC system installations is to make all power supplies common to a Earth ground star point.
I have just used opto's to transition from one power level to another, but either side is ground common.
Although the the PC MB/P.S. is at ground potential via the power cord, I also ensure a bonding conductor from the PC chassis frame to the star point.
So far this method has served well.
Al.

[leaveme]

Thank you man for your information.
In powering sequence, which one you prefer to switch on first: controller or PC?

[Al_The_Man]

Usually the PC, as the servo control power is usually off in E-Stop condition, If I were using Mach, I would use the charge pump to act as a watch dog and prevent all motor power until the PC & program were active.
The output of the charge pump/W.D. would be in the E-stop string, this is common in industrial equipment.
Al.