On a PRS Alpha, what is input #1?

[dray]

when I hqave sb3 open and cutting input #1 is flashing intermittently and causing it to mess my wood!

Is this the USB interface?
What can I do to fix this?

Thx
Danny L. Ray II

[Ryan Patterson]

The Z-zero plate is wired to input number 1. It is probably flickering as the tool moves and the Z-Zero plate is touching the spindle.

[dray]

Ahhhh makes perfect sense!

[paco]

It shouldn't make you any trouble even if it's flickering... unless your input #1 is monitored to do something if it change while cutting file is running.

Mine id flickering all the time (because I hold the Z plate with a metal clip in the carriage) and it never did anything to the machining process.

If it really happen to create problem, isolate the Z plate (or the grounding source). That's why SB provide a plastic holder.

[dray]

I did isolate it.. still unsure if that was causing problems. I was re-surfacing the table and it was chattering, I noticed the flickering on #1 and thought that was the cause..

I am thinking of using firewire to serial to speed up data transfer has anyone done this?

[myxpykalix]

Do you have dust collection, and is it grounded?

[dray]

no its not grounded.. Think it would make a difference?

[paco]

From the default settings and routines, only the Zzero and probing routines monitor input #1. Unless you have customized routines or very special purposes cutting files that monitor input #1, triggering of input #1 would not do anything. Try it; make the tool move along the X (MX, 96) and while it's moving, touch the Z plate on the bit or any other grounding places.

The jerky/hesitation/chocking you're experiencing is most probably cause by a control PC that is not optimized. This happen mostly at high move speed right? That mean other software(s) are running in the background, USB serial adapter not configured properly or on a USB 1.* rather than on a 2.0, not enough memory or CPU resources...

Input #3 is, by default, monitored as limit switch system. If input #3 is triggered at any kind of move or jogs, it'll stop the tool.

Does that make sense?

I tend to think that your Z plate circuit maybe grounding somewhere which is why it's flickering even if it's isolated.

[paco]

If the DC is not ground properly, it can trigger input #3 (limit switch system) and #4 (E-stop). You can install a "filter" for that. It can "disconnect" the control box from the motors and the control software; that need a grounding fix... It can set your shop on fire; I think you might already know about that part... It can, in most case, not create any problem what so ever and it's easy to isolate if you think it's causing the problem; just don't run the DC for some time.

[fleinbach]

Danny,

"YES" it will make a lot of difference. An ungrounded dust collection hose will play havoc with the data. It may be fine on a number of cut jobs and suddenly when you least expect it things will start going wrong.

Here is a link describing how to ground it properly here (http://www.talkshopbot.com/forum/show.cgi?tpc=7&post=20736#POST20736)

[myxpykalix]

As already stated YES it will ruin you. I had a ungrounded dust collection and was cutting a lot of mdf. While cutting a file everything would just STOP or FREEZE. I would lose my 0,0 point and have to try to get it back and restart the file. This would happen 3 or 4 times within the same job. I read here about grounding the dust collector.
I took a spool of unshielded braided copper wire grounded one end to the carraige and ran it thru the length of the hose and grounded it to the housing of the dust collector and to this day i have not had another incident of shorting out.