breakout board schematic

[giorgiocnc]

Hi everyone,

I ran across this breakout board schematic on the net, and I was wondering whether it is useable or not. It seems like a nice card with optocouplers, but I'm not sure if the design can be trusted or it does nothing but magic smoke in my PC.

Any reply is appreciated.

Giorgio

Galery link

[pminmo]

Hmmm, not sure why several things were done the way the were. Unless the wall transfomer wasn't really an transformer, don't see any benefit to the majority of the optocouplers. I didn't see anything on the board that would cause your PC to smoke, beyond that............

[giorgiocnc]

Thank you Phil for the reply.

I'm still thinking in building this one.
Aren't the optocouplers supposed to protect against power surges? Which ones you think are not necessary?

Giorgio

[pminmo]

Giorgio,
I sent you a private message with my thoughts on the circuit.

[weedy]

Originally Posted by pminmo Giorgio, I sent you a private message with my thoughts on the circuit.

Hi, pminmo.

I want to construct the 3-axis opto interface pcb card in your site and I have some questions (note: I am very weak in things electronics but can learn quite fast):
1) I have a stepper drive very similar to the Gecko 201 (opto isolated input as well), can your opto interface card be suitably use with it? Or, is there no need for opto isolation anymore?
2) Do you have an interface card that has relays for various inputs?

TIA.

[pminmo]

Originally Posted by weedy Hi, pminmo. I want to construct the 3-axis opto interface pcb card in your site and I have some questions (note: I am very weak in things electronics but can learn quite fast): 1) I have a stepper drive very similar to the Gecko 201 (opto isolated input as well), can your opto interface card be suitably use with it? Or, is there no need for opto isolation anymore? 2) Do you have an interface card that has relays for various inputs? TIA.

1. If your drives are opto osolated, so there really isn't a need to further isolate them.

2. No I don't. Let me explain why. Mechanical relay's switching heavy currents or inductive loads "spray" electical noise in physically close wire, pcb lands, component leads, etc. My "interface" cards have one or two solid state drivers on them to drive an offboard solid state or mechanical relay so you can physically locate that device away from the logic circuits and wiring of the interface and motor drivers. I just see doing that as an opportunity to setup a potential intermittent problem in some systems. If at all possible, use a solid state relay in your setup. Second I don't like running line voltage ac onto a board that isn't covered for safety reasons, as well as a higher potential for serious damage to connected devices, PC, motor drivers if a fault were to occur.

It's just the way I do things.

[weedy]

Originally Posted by pminmo 1. If your drives are opto osolated, so there really isn't a need to further isolate them. 2. No I don't. Let me explain why. Mechanical relay's switching heavy currents or inductive loads "spray" electical noise in physically close wire, pcb lands, component leads, etc. My "interface" cards have one or two solid state drivers on them to drive an offboard solid state or mechanical relay so you can physically locate that device away from the logic circuits and wiring of the interface and motor drivers. I just see doing that as an opportunity to setup a potential intermittent problem in some systems. If at all possible, use a solid state relay in your setup. Second I don't like running line voltage ac onto a board that isn't covered for safety reasons, as well as a higher potential for serious damage to connected devices, PC, motor drivers if a fault were to occur. It's just the way I do things.

Hi, Phil. Thanks for the detailed explanation.

1) Since I don't really need the opto-isolation, will the "Single Sided 4 Axis Interface PCB" be more suitable for my purpose? And will it have no conflict connecting to a "Gecko-like" driver?

2) Understood. Thanks for the info.

Weedy

[pminmo]

Actually my interface boards are more geared to the open source boards. You would need to use the solder pads of the idc connectors. If you are going to do that, why not just wire directly to a db25 connector?