Gecko triggered E-stop circuit?

[sol]

Here is a circuit that I am preparing to solder up but thought that it would be wise to ask those who know far more than I do to look over my shoulder.

The goal is to allow any one of the three Gecko 320s to trigger a software-stop via the relay which will be in series with other panic stop switches...all normally closed, active High.
I have played around with different resistors and transistors in this circuit and the ones shown seem to give the best bench-top results...but yes, I know The Real World is different.

Mariss has a sophisticated circuit on Ya-Gecko-hoo groups but it is more than I wish to deal with or need.

Thanks for any input!

[rc-cellar]

Seems way too simple ... anybody tried it yet?

Anyone have the link to mariss's controller on Yahoo? ...would like to check that out too.

[sol]

Wow, I forgot about this dormant post from last fall.
Yeah the circuit works fine and is part of my control box now.
One thing...the 5v is from the Gecko's encoder terminals, not the power supply.
I tried to post the updated schematic but it is too big for the forum so here is a link.

http://solsylva.com/cnc/8cnc541.html

[rc-cellar]

Thanks Sol... I had 1 axis fault while cutting and......well fortunately the only thing that broke was an endmill. I don't want that to happen again. I have a latched E-stop ckt so I'll just tie into that.

Quick question on the 5 volts. I have seperate 5V supply for my encoders. Gecko 5V are not used (470 ohm jumpers).
Would I ....
A) use One of the Gecko5V to supply all three opto's
B) or use Each(3) Gecko5V to supply the corresponding opto.

Also, I recall the max output for the encoder supply being 50mA... enough to drive a relay(?)

Any input appreciated!

[Al_The_Man]

Originally Posted by sol I tried to post the updated schematic but it is too big for the forum so here is a link.

I would have thought that 10k into the anode of the 4N25 is pushing the limits a bit, less than 0.5ma LED current is just off the chart.
Al.

[rc-cellar]

I agree... 1K (5mA) should light 'em up better

[sol]

Yeah it is literally off the chart. http://www.fairchildsemi.com/ds/4N/4N25.pdf

Ya got me; I fried a few 4N25s using lower resistance before settling on the 10KΩ resistor by trial and error via an ancient resistance substitution box and a couple of Harbor Freight multi-meters; yeah, only the finest analytical instruments here.

A little learning (and a lot of forgetting) is a dangerous thing...but the circuit has been working for months now, so, uhh, Duh, I dunno.

[sol]

Originally Posted by rc-cellar Quick question on the 5 volts. I have seperate 5V supply for my encoders. Gecko 5V are not used (470 ohm jumpers). Would I .... A) use One of the Gecko5V to supply all three opto's B) or use Each(3) Gecko5V to supply the corresponding opto. Also, I recall the max output for the encoder supply being 50mA... enough to drive a relay(?)

Oh! No! I should clarify. The 5v not specifically labeled "Enc" is from the main power supply, not the Gecko's encoder power supply.
Yeah, I was real paranoid about the Gecko's 50mA upper limit...
And I used choice B, each Gecko...corresponding opto.

[rc-cellar]

Breadboarded today... seems to work fine with everything off main 5V supply.
Thanks a bunch!

analytical instruments ?? I just lick my finger and touch....

[alexalex]

Sol could you repost that schematic please....

[kong]

Hey Sol, just wondering if it will be safe to come off of pin 4 of each opto to a resistor then a LED? The other sides of the LEDs will go to a common ground.
Don't really want to blow anything whilst playing!

[Al_The_Man]

Pin 4 is the transistor emitter of each opto in the schematic posted, the transistor are all AND'ed together in series, or do you mean you want to add a LED indicator on each?
If so a led in series with the anode or cathode of the opto emitter diode, pin 1 or 2 will tell you which one tripped.
BTW you might want to drop the 10k value down to 1k at least as the 10k results in less than .5ma, especially if you add a LED indicator in series.
The chart shows 60ma average for the Opto LED.
Al.