Re: Gnds, and more Gnds and Gecko's Questions..........

--- In CAD_CAM_EDM_DRO@yahoogroups.com, wanliker@a... wrote:

> I am finally making progress on my control panel again, for the EMCO

Compact

> 5 CNC Lathe I am converting....
> Tim, will be here tonight and want to persuade him to help me set it
> up..............
>
> In the mean time I have questions about grounds,
>
> I am using an early Wonderboard that has two separate 5 volts

supplies. One

> is marked (Comp). The other is (Ext). The two +5 volts supplies are
> completely isolated from each other
>
> The first one is a +5 volts (Comp), supply with its ground connected

only to

> the computer ground, and the ground for the Opto Isolators on the

input side.

>
> Its +5 volts is providing, thru 1 K pull-up resistors, the power for

the

> input side of the Opto Isolators only, from the computer.
> It is not a +5 that comes from the computer itself, it is a separate

power

> supply, on the Wonderboard.

By using a seperate 5 volt supply the geckos and computer are
isolated. + 5 volts into the gecko and - to the computer port ground.
This is for powering the step and direction opto.

>
> The second +5 volt (EXT). Supply, is for the external Opto Isolator

circuit

> to the drives, it is feeding the output side of the Opto isolators,

I will be

> using these signals for the step and direction to the drives.

Don not understand your use of the second supply ?

>
> Questions:
> 1. When using the Opto Isolated circuit, do I still connect the

computer

> ground to the main power supply ground????????

No !

This would tie the controller

> to the electrically isolated Computer/Parallel port if I do......It is
> isolated now, with its own Opto Isolated circuits and the separate

+5 volt

> (Comp). Power supply, on the Wonderboard.


>
> 2. Am I correct, that, the +5 (EXT). volt supply that feeds the

output side

> of the Opto Isolators, is the same + 5 volts that goes to the

Gecko's?????

> This output side is where I am getting the step and dir signals for

the Gecko

> 320's.
>
> 3. Do I do anything with the Ground of that +5 volt (EXT). supply??

This is

> the Ground that is for the output side of the Opto Isolators that

are feeding

> the step, dir, and +5 volts to the Gecko's.
> I have it connected to the controller main power supply ground now,

is this

> correct???

Again , the step and direction lines and + 5 volt (common) is not
connected in anyway to ground or power inside the gecko.
5 volts into the drive, out the step & dir lines, though the computer,
and back to your (EXT) supply.
Or should it be floating??? Or connected some where to the

> Gecko's?????? This is the - of the +5 going to the Gecko's,

assuming I am

> correct in question #2.
>
> Gecko 320 questions:
> EStop
> 5. I am using relays to select the power on and off to the Gecko's,

for

> driver selection. The cabinet has X, Y, Z, and A drives. For the

lathe I

> will only be using X and Z, later the same cabinet will be

controlling a

> Mill, and using X, Y, Z, and sometimes A.
>
> The relays drop out under an EStop or Fault, I have 470 MFD caps

mounted

> right at the Gecko's G-320 terminals.
>
> 6. When dropping the relays with an EStop or Fault, will this cause any
> problems for the Gecko 320's?? Can I drop/isolate both the Power

Supply +

> and - with the relays or will dropping both cause a problem for the
> Gecko's??? This would happen in an E stop or Fault situation only,

or if the

> drives were not selected for operation.
>
> 7. I have some 1000 MFD capacitors, that I could mount at the

output side of

> the relays, would this be good for the G-320's in an EStop Stop

condition or

> Fault to allow them to have more capacitance during shutdown?????

Assuming

> breaking both the + and the - at the same time.

I would just use dip switches to the err/res lines and switch in
drives to the reset button that you need active. The drives output is
disabled with a fault ,... no need to use relays

Frank

>
> bill
> The longest member of the group without anything running.............