[GEBrown]

In trying to solve a more practical problem, I noticed that I have 11 volts of DC between my Inputs 1-4 and Grnd. Does that seem right?

You can see in the attached pictures that I'm feeding my Gecko 48V (nominal) and I'm getting about 11V between input pins 1-4 and Grnd. I thought this was weird. I didn't take pictures of all 4 inputs, but take my word, it was the same.

I have my limit switches on input pin 1.

Is it correct? (The voltage, I mean - not the limit switches )

Thanks in advance.

Gary

[Al_The_Man]

From what I gather the input sinks a Opto input to 12v Common, so open circuit, you would see anything around 11v-12vdc.
The biggest problem out there is that many BOB manufactures do not show the nature of the input and output in order to make an informed decision when using anything but a contact closure switch etc.
Al.

[GEBrown]

Al,

Thanks for the fast reply.

I will open another thread to ask my "more practical question" that I referred to above.

Gary

[Al_The_Man]

I will open another thread to ask my "more practical question" that I referred to above.

Gary

You mean it didn't answer it?
Al.

[GEBrown]

Thanks to Al, I was able to establish that is is normal to see ~12V between input pins 1-4 and grnd on a Gecko G540.

http://www.cnczone.com/forums/gecko_...en_inputs.html

So what I have been trying to do is to install an optical switch as a home switch - without success. The particular switch I am trying to use is the Opto Endstop from Makerbot here:
Opto Endstop v2.1 Kit

Now, this switch (like others) is designed to pass 5V between the collector and the emitter when the switch is open (in this case). When you block (aka flag) the switch, it opens the circuit and 0V is detected. (aka active low, I believe.)

So, in other posts, it has been said "All you have to do is connect the collector to grnd and the emitter to pin 1-4". I'm working from memory, so maybe I got those backwards.

But, in my case at least, I can never get Mach3 to detect that the Opto switch had been triggered. And so with the realization that there is always 12v across the pins and ground, I think I see why.

I'm in no way electronics savvy, but am I on track here?

If so, how do you get the Gecko G540 to detect a signal that goes from 0V to +5V?

Or do you not?

Thanks guys!!

Gary

[Al_The_Man]

It saves some time if you explain off the bat what you want to do.
BTW that is expensive for a slot opto, you can get them from DigiKey for around a $1- $1.50.
The trouble with a kit like that is that it is designed for a particular interface, so if you use any different/voltage configuration, you have modify the design for the interface you are using.
In this case of Gecko it is a 12vdc sourced Opto.
I, or someone here can show the change you need.
Al.

[GEBrown]

Al,

Sorry, I wasn't trying to waste time, just trying to keep a single topic on a single thread.

I would be pleased if you could show me the change I need.

Thanks in advance,

Gary

[Al_The_Man]

Well looking at the G540 documentation I do not see the source of the 12vdc for the inputs, just the common, you would need to access this to supply the interrupter, If not you need to supply your own 12v, the commons would be tied together at terminal 12 and the 12+v would go to the VCC on the circuit board.
The 220 R2 is a bit low, I would change it to 330. R1 you can probably leave out.
The V0 would go to the Gecko input.
Al.

.

[GEBrown]

Well looking at the G540 documentation I do not see the source of the 12vdc for the inputs, just the common, you would need to access this to supply the interrupter, If not you need to supply your own 12v, the commons would be tied together at terminal 12 and the 12+v would go to the VCC on the circuit board.
The 220 R2 is a bit low, I would change it to 330. R1 you can probably leave out.
The V0 would go to the Gecko input.
Al.

.

Thank you Sir!!!

Gary

[762x51]

Here is a schematic that Marris posted on the Yahoo Gecko Group geckodrive : Geckodrive back in 2008. Probably out of date but I suspect the I/O is still similar. Anyway, hope this is of some help to you.

[Al_The_Man]

It appears from the PDF that the +12v is not available, it originates from the 7812 IC.
The separate supply may be the only recourse?
Al.

[GEBrown]

I've got plenty of 12V DC sources - I'm only running 1 hard drive in my controller PC, so all those spare HD connectors carry 12V and 5V.

Thanks for the input all!

Gary

[GEBrown]

I just wanted to get back and give an update on my problem. I finally got back to the optical home switch this past weekend. I followed Al's instructions - desoldered the 220ohm and replaced it with a 470ohm (I had it on hand) and now my switch works PERFECTLY!!

The LED even still works! I was afraid it would get blown out by the increased voltage (12 vs 5 volts).

THANKS again to Al - you are VERY helpful.

Gary

[Mariss Freimanis]

I'm sorry I haven't replied to this thread even though I have been following it. Let me explain the reasoning behind the G540 inputs:

Many other systems have noise issues with switch inputs. I was aware of this and I designed the G540 to be as immune as possible to noise that plagues other designs. There is no magic to solving this problem; all that's needed is a large voltage swing on the input (12V vs 5V) and slow interface logic to the input signal (CD4000 series CMOS logic vs. 7400 anything logic). It has been very successful, I cannot recall a single application instance that resolved to input noise as being a culprit. I also know the 12V interface is an issue with some users.

The G540 has had a phenomenal run since its introduction in 2008. After all, it was originally designed as a demonstration platform to showcase the G250 drives.

The G540 is up for a top to bottom redesign. We have a long list of things people don't like about it and what they would like to see different about it. Top of the list is to get rid of the wretched DB-9 connectors. Second on the list is to change it from panel-mount to chassis mount. Third is to show which drive lights the dreaded red LED and to disconnect it if it's a failed drive so the remaining three can still function. Finally, the motherboard and sheet-metal changes will be designed to accommodate the upcoming GeckoMotion stand-alone motion controller requirements of the upcoming GM540 version. Much more on that after the GM215 drive comes out in November.

Mariss

[GEBrown]

Mariss,

Thanks for the update.

I, at least, will be anxiously awaiting the new models.

Thanks!!

Gary