Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: Overloaded on November 16, 2007, 08:06:02 PM
-
I am in need of a breakout board.
I see many on eBay but am not sure of what I need.
I'm building a small lathe, 2 axis, maybe a relay for the spindle and one for coolant.
Input requested.
Links to reliable designs, suggestions welcome.
Thanks
-
I used this board on my knee mill, and have had no problems and good support.
http://www.cnc4pc.com/Bidirectional_Breakout_Board.htm
olf20
-
olf20
That looks good, good price too.
I see they also have a dual relay board for $18.
I also notice that this one is not opto isolated.
Is the isolation necessary ?
Thanks
-
"Is the isolation necessary ?"
You are going to strike quite different opinions on that question.
Really you need to read up a bit and make your own decision.
Just know that there are many builders very happily using those particular boards with no problems. Me included.
Optoisolation is a little bit overkill IMO. As you will soon see others will have a different opinion. ;D
Greg
-
Extra precautions have been taken when designing this circuit, by taking into consideration the extremely high voltages that stepper drivers can achieve and lack of experience that some users could have in wiring circuits of this kind.
Greg,
The above is from CNC4PC catalog.
It appears to me that the primary reason for isolation is the chance of inadvertent mistakes when making the connections.
After the connections are properly made, does the isolation offer any benefits ?
All I read about is fried ports being expensive to repair...especially on laptops.
Thanks for the help.
-
hi,
for my two-pence worth, I would not use a break out board,and thats nothing to do with cost cutting.
firstly, practically all stepper/servo drives have optoisolation built in.so it is purely to safeguard against bunging
more than 5 volt back down the port by mistake.Treat your port with respect!
Alternativly use a pci card,best to use them +5volt common though (as a laptop) taken from a spare usb port.
Secondly,if the optoisolater or its wiring isnt quite right,that can be a bitch to trace,giving you mis-steps, and
hours of fun! Some drivers,aparantly dont like being fed through secondary opto's.
Just my opinion!
Tony
-
This is new to me.
I have not seen or heard of this before. (limited exposure)
I see where it would go in the PC, beside the modem I suppose.
How would you use it with a laptop ?
Can you tell me where I can find more information on using the PCI card for this application ?
Thanks Tony,
Good stuff
-
i agree, breakout boards have given me endless hours of troubleshooting to remedy lost steps.i use 1 but only for inputs and relay outputs.a heads up on an ebay seller wilhelmjason.a dispute this guy resulted in him threatening to target me with his hacker forums to spam the crap out of me.real creep.
-
Man ! Thanks for that , I use eBay quite a bit.. been lucky so far.
I'll make a note on this guy.
Thanks for the heads-up.
only for inputs and relay outputs
I assume that you mean inputs to the PC like tach, home/limit switches and encoder feedback ?
And relay out to spindle motor, coolant and the like ?
And the step/dir are directly from the PCI ?
I'm still interested in more info on this.
Thanks
-
Greg,
...................It appears to me that the primary reason for isolation is the chance of
inadvertent mistakes when making the connections.
After the connections are properly made, does the isolation offer any benefits ?
All I read about is fried ports being expensive to repair...especially on laptops.
Thanks for the help.
I'm not interested in participating in a debate about connection methods but as you asked me a question I will not be rude and ignore it.... :D
"After the connections are properly made, does the isolation offer any benefits ?"
I can't think of any. Over the life of a machine faults may develop. It might help here.
More likely I think with a self built machine you will at some time start making alterations to incorporate some new beaut feature. Maybe then it might help. :)
"All I read about is fried ports being expensive to repair.........."
I've been following this forum among others for a while now.
About once a week I read about someone who has fried drivers, power supply or some other component.
Can't remember a report of a fried printer port. I'm sure it happens. I don't think it happens very often.
I use a PCI printer port. Costs about $20. Probably the cheapest component in my control setup. I don't lose sleep about it. :)
".........especially on laptops."
I certainly would not use a new expensive laptop in my shed. Dusty very anti laptop environment.
However I have used an old laptop that has been retired from daily use. Not worth much. :)
Greg
-
Valuable input...Thanks Greg.
The PCI has a DB25 connector.. correct ?
Do these wires then go directly to the step and dir terminals on the drivers ? No other board necessary. ?
Where can I get a diagram or schematic of a typical hook-up ?
This sounds to me like the way to go.
Thanks again
-
hi, i am connected thru 2 pci parrallel port cards.one is being used for outputs to larken viper drives and manual pulse generator. . the other pci port is connected thru a sound logic breakout board which has safety charge pump and onboard relays . works for me.the onboard parallel port on the motherboard i have disabled.if your drive has isolation already, why add another buffer between them?
-
Sounds reasonable to me.
Any Idea where I can get a diagram or schematic ?
Thanks
-
........................The PCI has a DB25 connector.. correct ?
Do these wires then go directly to the step and dir terminals on the drivers ? No other board necessary. ?
Sorry you have misunderstood. I was downplaying the need for optoisolation.
I would still use the board we mentioned before from CNC4PC.
Makes hook up easy and buffers low logic voltage which is common on most computers (not just laptops)
Greg
-
Greg,
I believe I've got it now....duh.
I think what threw me was.... (I'll try to do a quote)
hi,
for my two-pence worth, I would not use a break out board,and that's nothing to do with cost cutting.
Tony
I guess what Tony meant was he would not use an OPTO ISOLATED break out board, not no board at all. It's making better sense now.
Sorry to get you tied up in this DEBATE that you warned about earlier.
I'll let it go for now but forgive me if I bring it up later.
You've been a BIG help,
Thanks
-
Hi,
yes I use passive breakout boards.
and good quality shielded data cable(twisted pairs)
be sure to only ground the cable at one end. Not sure why, but
its apparantly good practice?
Tony
-
Hey Tony,
I should have realized what you meant initially. Chalk that one up to inexperience on my part.
Which end of the cable shield gets grounded ? Does it matter ?
Also, I searched around the net for PCI cards and am more confused than ever.
$100 to $1000 is all that I saw.
Can you or anyone else provide a link to what is commonly used for "our" applications ?
Thanks one more time.........
-
HI,
if you look on Ebay you should be able to pick one up for about 10-15 £ 0r double that for dollars.
heres one:
http://cgi.ebay.co.uk/High-IEEE-1284-Parallel-Port-PCI-Printer-I-O-Card-UK_W0QQitemZ260183882206QQihZ016QQcategoryZ96880QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
If your not an ebay member join up,as most of us buy the bulk of our gear from there!! Also open yourself a paypal account.
its the best and safest way to transfer monies via the net.
The shielding is usually grounded at the driver end,I ground every thing ie computer/machine/drivers and the ground is linked to 0volts andI use servo's so there's loads more wiring.
hope that helps?
Tony
-
TONY, if you ground at both ends you have created a loop. The loop can then generate current(bad). If single ended all the stray stuff can do is bleed off to the single grnd point. That is why you also never want to daisy chain the grn. Single point is the way to go.
Just a thought, (;-) TP
-
I guess I'll have to voice the lone pro 'opto-isolation' opinion here. Opto-isolation is useful for far more than protection from getting things hooked up wrong the first time. When properly designed it will electrically isolate the computer from the machine. The primary advantages of this isolation are noise reduction, electrical protection of the host computer and interfacing dissimilar voltages. In some cases this isolation is essential, and in some cases not.
I built an opto-isolated breakout board for a Dyna-2400/Mach III conversion I did. It used all the original drives on the machine. The opto-isolation insured that no noise from the steppers/drivers got fed back to the computer. When I was looking at commercially available boards I was surprised to see some that seemed to have a single onboard transformer to provide power to both sides of the opto-isolation circuitry. That kind of blows the whole point of opto-isolation.
I'm finishing up a Mach III conversion of a Bridgeport Discovery 308 VMC now. It uses a Galil motion control board and ICM-2900 'break out' moudule. The encoders, limits, homes and operator interface buttons are not opto-isolated. They are powered by the ICM-2900/Galil and in shileded cables. The 'extended I/O' which controls both 24VDC and 110VAC. This was done through 'Opto-22' racks, which hold individually opto-isolated SSR's. This completely iso-lates all the higher voltage and 'noisy' signals from the control.
-
Jeff,
yes those opto22's are great I use them whenever I need to switch AC from 18-230 volt.
Plus there forever coming up on ebay for next to nothing!
I supose with my builds I take a "minimalist" view,and I never use an expensive controller computer.
as long as its 2gig and costs less than £100 then its a winner.
Tony
-
Good job Jeff.
Overloaded, look at this link. http://www.rogersmachine.net/PCIport.html
Also, tiger direct, new egg, and others will have dual cards. That is what I use in conjunction with BOBs
Brett
-
EXCELLENT !
MUCH good input.
Jeff, I can see where isolation may be essential as you say in some cases.
I'll dig a little deeper before I place an order.
The common transformer set-up does seem strange, hmmm ? ?
Thanks for your input.
Tony, good tip on the shield grounding, I'll do all I can to control the noise.
Brett, thanks for the link. Tiger has a dual for $22. If I were to use 1 or 2 MPG's on my project, the added IO would be necessary, would it not ?
They have a single for $14. Cheaper than I expected. Description says that they are 3 times faster than the motherboard port. I take that to be a plus as well.
Much thanks to all
-
This just in:
Maybe I should think twice before ordering a PCI board from Tiger.
Here are some reviews from their site. Anyone had this sort of trouble with PCI's ?
Rogers Machine may be the way to go.
REVIEW BY: jwines1 Reviewed Sep 21, 2007
Would not work on XP tried every driver on the disk, was not Cables Unlimited card, nothing like the picture shown, waste of money
REVIEW BY: Plain Reviewed Sep 07, 2007
This port's drivers simply would not install in a WindowsXP box. After hours of trying I gave up. An email to the manufacturer resulted in a boiler plate response. When I replied to the email telling them it still didn't work, I got no response.
REVIEW BY: Bigtexan Reviewed Apr 04, 2007
I'm using XP and all I had to do was plug the card in and go. It took care of everything with no problems.
REVIEW BY: tbe6 Reviewed Mar 01, 2007
xp would not accept it. sent me an old board,9835 rev c. after reading install directions(had better in my dos days)i gave up and went looking for a real board.
-
hi,
forwarned is forarmed they say !
if The main chip says Netmoss on it it should work fine
Tony
-
Anyone have experience with this: Opto-22 SSRs turning on/off & powering a coolant pump?
I'm about to hook up the flood coolant motor so it will turn on/off via Mach 3 -- it's 110vac @ 1amp (although start up load is what 3 amps?).
I plan to use the Optp-22 and I have SSRs that "appear" to be far higher rated an that. But there's something about hooking up a motor to SSRs that I don't quite understand...
But I live in fear --> A couple of years ago I burned up a Hydrodraulic Valve Solenoid and an Opto-22 (Ethernet Snap) SSR (back plane was OK because it's "opto-isolated!). In that application the SSR also appeared to be rated for the load -- obviously I'm not an electronics expert, as such I'm concerned that I'll burn up something -- like the motor and/or SSR. I'm told the duty cycle/load of a solenoid is a different beast than a motor. But that doesn't resolve my concern. As such the coolant motor is plugged into a wall socket and light switch...
Suggestions? Is the best solution to put a mechnical relay in as well -- isolated the Opto-22 isolator as it were? If so, then I'll pop in a 110v relay. But hey if the SSR can handle it, that one less thing to wire in.
I realize that any suggest is "use at your own risk".
--Scott (fastest e-stop button user in the world).
-
I don't have any experience with the Optp but, putting in a relay sure is a "cheap insurance policy". If you blow a relay, it sure is easy to pop it out of it's socket and replace. Would it be that easy to recover if you blow your Optp?
Just my $.02
Sid
-
Oh that's worth a lot more than $.02! ;D
-
I am using a breakout board - from Routout CNC (in the UK) - I don't think he makes them - just markets them. It is a "dead" board and just provides any easy way to connect to the computer - and a good strong terminal strip in my "box of tricks".
The connections to the stepper driver boards (also from Routout) are direct from the breakout board. Wirng is so short that no shielding is necessary. I find outputs, for spindle motor, and coolant are best done via relays. Mine are 5v driven direct from the breakout board via a Darlington array chip - all four relays from the one chip. The relays are then connected to the Omron spindle drive inverter, and to the fluid pump. If you need a bigger relay - then keep the small relay - and just get it to drive the bigger relay - don't mess about with different voltages etc.
All my limit and home switches (see "laser gun sight") are wired at 5v - and linked directly back to the breakout board.
So - do you need opto isolation - then only trouble is - if things won't work it is a devil of a job finding where the fault is if you are trying to check voltages and everything through several "stages" - and the more complex you make it, the more likelyhood you have to make a wrong connection.
I have everything going into my control box on DIN plug connectors, or external connector strips. If anything goes wrong, I can unplug the affected bit and test it - in isolation to the control box. - then open the box and quickly test from the computer to the connector using the breakout board - which is easily accesible. I also have direct access to what the computer is putting out.
In my opinion - and I am aimed at the amateur/semi professional end of the scale - keep everything simple. Try and plan everything to use just one voltage at "ground" level - which avoids any likelyhood of feeding something nasty back to the computer. Isolate simple switching via relays - which guarantee a clean voltage seperation. I must admit that, with drives you are in the hands of the manufacturer, maybe so far I have been lucky. I use seperate boards for each axis, I am unlikely to blow all three at once - and replacing one board is a simple and relatively cheap job. I have just blown one on the Xaxis forcing the motor to push a tool against the workpiece - quite by accident, whilst I was testing something else - the replacement should arrive today.
As for Stepmaster boards - I used them, but found their marketing etc a bit convoluted and long winded- they seemed to work well enough though.
I blew them connecting the power supply the wrong way round one day ( a thing I have now protected against by using a big diode bridge on the input). I use Routout bacause they offer good delivery times here in the UK.
-
You need to be sure that you are selecting the correct SSR for the job and providing it with a proper heat sink. I have yet to kill an Opto-22 SSR. Check out: http://www.opto22.com/documents/0859_Solid_State_Relays_data_sheet.pdf, look at page 14 it gives model # recommendations for various sizes of electrical motors. Also triple check what your motor is really drawing, 1 amp at 120V is around 1/10 HP (maybe) are you sure your pump isn't bigger than that?
Would it be that easy to recover if you blow your Optp?
yep, they plug right in/out, no worries and are MUCH more reliable than mechanical relays. You can use the smaller (rack mount) Opto-22 SSRs to drive large contactors/relays etc. This is useful as it provides both the optical isolation of the SSR and the current capability of the relay.
Wirng is so short that no shielding is necessary.....if things won't work it is a devil of a job finding where the fault is if you are trying to check voltages and everything through several "stages"....Try and plan everything to use just one voltage at "ground" level - which avoids any likelyhood of feeding something nasty back to the computer.
OK, 'grounding'...'(earth)ground IS NOT equal to DC common. They do not mean the same thing, unfortunately we all throw around the term 'ground' very loosely. 'Ground' is this context refers to 'Earth Ground' which is a safety device. The incoming mains voltage is referenced to ground (through the 'ground' rod(s)) and so is your equipment. This provides a path of least resistance to shunt the voltage away from important things like people in case something goes wrong. 'Ground' SHOULD NEVER carry any current, it IS NOT a common return path for all circuits. That is the job of DC common, and your system may have more than one DC common which is not a big deal.
The problem is that folks think 'ground' is this universal reference for EVERYTHING in a system and try to measure voltage to it from any given point, which is wrong. Think of it this way, if I were to nail three pieces of wood together at odd angles and ask you to measure their length how would you do it? Would you pick the bottom of the closet piece of wood and measure from there to every other piece? Or, from the floor (ground) to each piece? Nope, because that would not tell you a thing. You would run your measuring tape from end to end on each piece of wood (so your reference is the beginning of each piece of wood and you are measuring from that reference to the end of the wood to find its length.) Measuring voltages is the same idea, you are measuring from a reference point (common) to some other point in the same circuit (same piece of wood).
-
Great reply and info. Jeff. Kinda like a tutor post. Your full of good information. :)
Brett
-
I have to disagree here...........
Opto Isolation is THE way to go. I was getting my 5 axis Shoptask ready for the Mach3 Convention SE. The computer motor board was old (BTW opto isolation works both ways). Any way I was using some first Generation C-10's from CNC4PC (the new stuff is isolated, the old was not). At any rate I was testing my machine, and something went BANG in my computer, and it promply died.......... I opened the case and some capacitors had Blown up (this machine had run for about 5 years), these caps took out my mother board and PP ports......
But that is not the worst, it also took out BOTH of my BOBs (I held these up and showed the participants of the show why ISO is good), and further when the BOBs went they in turn took out 3 or my 5 Geckos.......... Total cost: One computer, 2 BOBs, 2 PP's, 3 Geckos and lots and lots of Klenex tisssues for all the crying that I did.
The lesson is, sometimes it is NOT you, sometimes Electronics just go bad with age and Fail ALWAYS at an inopertune time, like 2 Days before a planned Demo.....
Scott
-
The lesson is, sometimes it is NOT you, sometimes Electronics just go bad with age and Fail ALWAYS at an inopertune time, like 2 Days before a planned Demo....
Very well put Scott...no wonder they invented opto-isolation :)
-
Great information (everyone)!
Perhaps I should (figure how to) create a new topic on this -- but it's slightly related to the current dialog...
What's the basic method for interfacing to the otpo-22 SSRs via Mach 3 I/O? Is there a plug-in enabling Mach 3 to "talk" with the Opto-22 SSRs on the break out board?
I did a quick search and didn't see one. For instance, given that the Galil plug-in allows an I/O interface, does it follow that there is an Opto-22 plug-in for I/O?
Or is it serial I/O? I read a while back that the Opto-22's ISA board (in my setup) is basically a common PC I/O interface board (Com ports or printer ports, I forget) that decodes commands sent to it and performs the respective I/O with the opto-22 SSRs mounted on the break out board.
I've written standalone code in C++ to interface with Opto-22's (ISA and Ethernet) using their Opto-22's programming library, but I'd rather not have to do that again for Mach 3 if it already's been done somehow .
--Scott
-
Sorry to jump on the band wagon re BreakOut Boards.
I purchased 2 "Parallel interface cards (c1)" from cnc4rpc some time ago. I cant find any info on their site about these cards any more - must be old model?
Will these cards give me any protection for my PC?
-
Try this link,
RC
http://www.cnc4pc.com/Store/osc/product_info.php?manufacturers_id=&products_id=47
-
Thanks for the link,
I have been there, but my board is not listed. Must be to old!
Thanks anyway.
-
The link is to the C1 product page.
Are you sure what you have is a C1 ?
RC
-
Here is a pic of the card.
Cheers,
Bruce
-
Hello Bruce,
That must be like you say, an older version of the C1.
I would say that it probably is buffered and isolated due to the fact that it need s a separate 5V supply.
On the newer ones, the chips are in sockets for easy replacement.
Several other options were added as well.
You could email Mr Duncan to be sure, he's always been happy to help and quick to respond.
His components are all that I use...and I've had no problems.
Regards,
RC
-
Thanks,
I will email as you say
looking forward to meeting a few like minded people at the may bbq
Bruce