Need Help!- Gecko G540 input question

[ronncat]

Before I start, please don't jump all over me for my question. While I have a good command of the english language, my understanding of electronics is VERY basic. I have done a search on my question, but lacking a PhD in electrical engineering, most of the replies went right over my head. I would appreciate if someone could answer my question in plain layman's language...

Here is my situation. I am converting an X3 mill using a Promica kit and the Gecko G540. The Promica kit includes optical homing sensors that operate on 5V. Here is a description of the sensors as provided by Marc, the owner of Promica.

"The optical sensor is basically a transistor that is operated by infra-red and the output will be ‘floating’ or pulled to ground (-ve) depending on the IR beam being there or not.



In my controller I use logic level signals ... I have a 5K resistor between the output and +5V. When the beam is broken the transistor stop conducting and the 5K resistor pulls the line high. When the beam is not broken the transistor conducts and pulls the line low.



Mach3 is configurable to see either state as ‘homed’ ... so you don’t have to worry about which state is ‘on’ or ‘off’ the switch – you can change it.



All you need is a 5 v supply across the Shield (-ve) and Red(+ve) wires and a resistor (around 5k) from the White(op) to +ve ... the White would also then be connected to any available input pin on the parallel port. I use a separate pin for each home (XYZA) but Mach3 can also handle a single pin for all..."


My understanding of Marc's explanation is that 5V is carried in a circuit from the 5V power source to the optical sensor. If the sensor is not obstructed, the current flows back to the negative pole of the power source. It does not flow to the output/signal line due to the resistor placed between v+ and the output/signal line. When the optical sensor is obstructed, current can no longer flow back to v- and therefore overcomes the resistor and flows down the output/signal line. So now the line goes high as there would be a 5V current in it.

The Gecko manual shows SPST relays connected to inputs 1-4 with an NC state. I assume that when the relay is open, the G540 sends a signal to Mach3 via the parallel port pins 10-13.

Now my questions. If I hook up the optical sensors to inputs 1-3 for my three axis, will it work? Will I fry the electronics because I'm sending current down lines that merely monitor continuity from the relays? (Input 1-4)

Should I bypass the inputs and tap into pins 10-13 on the parallel port? If I did, would this fry anything in the computer?

What is the best way to configure these optical sensors?

Please excuse my limited understanding of electronics, and if you would take the time to help, remember to speak in english, not electronese.


One more note aside...Is it possible to use the VFD to control the spindle speed of the X3 mill by sending the VFD output to the pot control on the mill. I have measured the voltage as 0-7 volts at the pot. Can the VFD output be limited to 7V so I won't stress the pot. Is there a way to configure that in Mach3?

Sorry for the long winded, multiple question thread. Thanks in advance to all

[Fastest1]

How sad you never got an answer. I truly hope you got it figured out. I too have quite a few questions about the G540 that DONT seem to be answered anywhere.

[blades]

That is sad. Fastest1, did you try to call Gecko directly for support? My G540 questions also went unanswered for the most part. This forum seems to be inadequate at best for noob help. You might try the bench mill forum, lots of those guys are familiar with the G540.

[Fastest1]

Blades, I was just doing my preliminary reading getting ready for the transplant. I do have the G540 and as I remember with the Hobby Cnc Pro kit I built there were difficulties getting the correct information. Almost like the sticky at the top of the Gecko threads (5) pages of renditions to the original instructions? Which should I use? Looks like Peter Homann has an opinion of how the G540 instructions should be worded also (nothing against Peter as I have run his products too). Seems like there would be a cut and dry closed thread specific to each model. With moderation of those specific posts to be done by the creator only. Maybe others could debate it but not on that thread. I have also noticed here as well as Hobbycnc's forums that if you ask a question that deviates a little from the norm it gets ignored. I finally got an answer about manually controlling a wired in relay and isolating the signal from back feeding the board with a diode. Am I the only 1 who wanted manual spindle/vacuum/coolant/light or whatever control? I really am not complaining as I have found that the pursuit of the answer in this hobby seems to be what I am after not the end result of machining something for someone else. When I built my Hobby Cnc board I put it in a metal case instead of the recommended plastic 1, you would have thought I did something horrific. I never got answers on that one, got it running thru persistence. I did learn alot about grounding and how to isolate them. You would not believe how many times that demon has surfaced!

[blades]

Fastest1, is sounds like your expectations of this hobby pretty much parallel mine: I'm working on a 7x10 lathe conversion, but the project itself is more the hobby than actually using it when I'm done, although that's yet to be seen. When the time comes for me to buy the G540, I suppose I will contact Gecko directly if I have very specific questions that aren't covered in this forum.

[Mariss Freimanis]

ronncat;

I found this post tonight. I try real had but I don't catch all of them. An otpo sensor is a single-pole, single-throw switch. Connect the emitter to G540 ground, connect the collector to any G540 input. All will work then.

Mariss

[Fastest1]

Blades, I started this challenge a few years ago. Someone somewhere said it was hard to understand and do. I guess that pissed me off just enough to jump in with both feet. I had no experience machining and though I work with low voltage electronics daily (I do custom home theaters), I really had no understanding of any of these products. The conversions and constant searching for the answers is what has become the challenge. At least when you are thru with your conversion you will have something that will cut almost anything.

Mariss,
Though I was frustrated when I originally wrote that response I do understand you are busy. The extra reading seems to be continuous part of this process. It is not plug and play though it is getting that way. Your products seem to be very well respected and enjoyed. I really cant wait to finish up and see my lathe run. I am very excited to see the comparison between it and my Hobby Cnc Pro kit I built a few years ago as that is the only other controller I have used. It had its challenges too.

[blades]

Originally Posted by Fastest1 Blades, I started this challenge a few years ago. Someone somewhere said it was hard to understand and do. I guess that pissed me off just enough to jump in with both feet.

LOL!!! Reminds me of a project I did a few years ago.... I told a buddy of mine that I wanted to turbocharge my little S-10 pickup. He laughed and actually dared me to do it.... so I did, from scratch. Turned out great!

I was a machinist for 15+ years, and I always liked the idea of table-top machining. Equipment is just cheap enough and parts readily available that it's really not that difficult. This forum also plays a very large part in the successful conversions that get done.