6b4

[rodm]

Thanks Mike,
I am getting used to the retirement thing now and can highly recommend it.
I suppose all the machines from that era have done a lot of work by now. Poor old Morphy has been working hard cutting 20mm plate for this build.

[rodm]

Would like to share my experience with some electrickery problems. As mentioned in an earlier post I had trouble with EMI on the limit switches and resolved that by putting 0.1uf capacitors across the input terminal to ground. I have done this before on advice of an electrical engineer and was confident it would fix my problem - it did.

In the last couple of days I noticed that the potentiometers connected to the Pokeys enabled console were fluctuating in voltage by .02 volts. Not much but enough for Mach3 to fluctuate by a couple of percent in the three functions they were controlling - Spindle Speed, Feed Rate and Jog Rate. It was annoying and you could hear it in the spindle speed.

I took a stab and placed the same capacitors across the input voltage and ground as well as the signal and ground of the pots. Result was a rock steady reading and a big grin from yours truly.

I know very little about electronics and I either jagged the solution or have done something that I shouldn't have. Being of the school that if it ain't broke don't fix it I intend to leave it unless somebody knowledgeable points me in the right direction.

This might seem like a trivial post but EMI and problems with low voltage signals can make a person pull their hair out.

[Bob Willson]

Good find Rod, but it may have just been loose connections.

Did you try tightening up all the connections first before replacing the caps?

[rodm]

Hi Bob,
They are soldered joints on the pot and at the other end screw terminals on the Pokeys. I don't think the screw terminals would have been a problem as I am very careful with electrickery. Not saying it wasn't though so I accept your point.

My method of tightening is to turn it until you strip the thread then back it off half a turn.

[Bob Willson]

That does sound like it is your normal method Rod, a bit like running the gantry into the end of the machine to square it all up.

Do you have a tester to measure the capacitors capacity?

[rodm]

I can't get away with much with you around.

No I don't have a tester but know of a couple of fellows that would have that sort of gear. I am lucky to have met up with a couple of electrickery experts on the CNC journey and while I don't like calling on them they are more than happy to help if needed. One of them is into Robotics and Animatronics and is well beyond my thinking.

The caps are 0.1uf value and I got them years ago I think on the advice of Greolt to solve limit switch noise at that time.

I got an email back tonight advising me to do exactly what I did with the caps so looks like I jagged a solution. The next option according to him was to place a small resistor in the circuit but he would need to calculate the value. This is really all mumbo jumbo to me and not something I enjoy.

To get away from electrickery I have been making the final touches to 6B4. Hold down clamps, spoilboard and have been typing up my notes of circuitry and pin assignments. I consider documentation important and it has saved hours tracking wires in the past. I thought of you during the process as I still use your word table, modified of course, for the Homann digispeed to the VFD configuration. It ends up a huge document with the configuration files and manuals for all the boards. All up there are 10 boards in this machine which means there are lots of wires interconnecting. Glad that is finished now.

[Bob Willson]

To get away from electrickery I have been making the final touches to 6B4. Hold down clamps, spoilboard and have been typing up my notes of circuitry and pin assignments. I consider documentation important and it has saved hours tracking wires in the past. I thought of you during the process as I still use your word table, modified of course, for the Homann digispeed to the VFD configuration. It ends up a huge document with the configuration files and manuals for all the boards. All up there are 10 boards in this machine which means there are lots of wires interconnecting. Glad that is finished now.

Wow, that sounds like quite a document. Is there anything in it that would assist others on this board who may not be aware of the benefits of documentation?

I'm really pleased that I was able to help in a little way, as I always feel that I take far more than I am able to give back.

[rodm]

Bob,
Your help is grounded and you are quick to help all posters.

The bulk of the documentation is manuals and I make notes as I go on schematics in the manuals - they end up a bit dog eared because of this. Wiring colour and what that pin connects to being the important points.
Where it is impractical to do that I use tables of which I have attached a couple of those - including your modified document. I also save on a thumbdrive the MachXML file, Mach3 brains file and any call to macros I have created as well as the Pokeys config file. The files are a safeguard in case of computer failure.

I have attached a couple of the tables to show what I do.