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nosisuzu
11-26-2008, 03:44 PM
I originally posted this on computerchristmas.com, but it looks like this forum sees more activity.


I use a series of 16 channel 595 boards with built in triacs that I made 2 years ago. To control the boards, I use an IBM server with Vixen loaded on it. When I run a sequence, the first 24 channels work fine, but after that the control deteriorates. Higher numbered channels flash at the wrong time or the wrong channel will flash. I let it run the first year, but last year I didn't have time to do any further troubleshooting and just ran the lights on a random flash sequence. This year, I plan on figuring this out! With that in mind, I designed this board with a 74HC14 chip to clean up the signal. I'm using the LED's as my pullup resistors, a method I've used in the past without problems on other circuits. The fuses are fast acting 3A to protect the server from the boards. Any thoughts on whether or not this board is a good idea? Does the board layout look OK?

If this doesn't work, I may try lowering the voltage to the 595 chips...

BadWolf
12-24-2008, 11:34 AM
I added your circuit to the input of my Grinch and finally, the Grinch works as it should.

Before added the buffer, I tried it on 3 different computers, added a printer port card to one computer, lowered the voltage to the Grinch, all to no avail.

I didn't make a circuit board, but built it on a piece of breadboard. I used a different chip, the 74ACT04.

Later. . . . . .. Brad

A Marchini
12-26-2008, 04:01 PM
I added your circuit to the input of my Grinch and finally, the Grinch works as it should.

Before added the buffer, I tried it on 3 different computers, added a printer port card to one computer, lowered the voltage to the Grinch, all to no avail.

I didn't make a circuit board, but built it on a piece of breadboard. I used a different chip, the 74ACT04.

Later. . . . . .. Brad

This issue has been discussed on computerchristmas for a long time now. I personally used the 74HC04 and it appeared to work well, but others tried it and it didn't seem to work for them.
This never made any sense to me. If you were outputting proper signals and had sufficient drive behind them, this should just work. I think the issues were people trying too many variables at the same time and once something worked not really going back to find out why an output driver didn't help.

In the end I guess it doesn't matter as long as there is blinky-flashy in the end.

Tony M.

Toaster
01-09-2009, 08:38 PM
What format are these files in? and is this supposed to help with mis-fire's and random blinky-flashy? Thats the issues I'm having on a 256ch olsen 595 (4 board) setup.

I have NOT taken down my lights, in hopes to trouble shoot this NOW, before next year.

THANKS.

A Marchini
01-12-2009, 09:51 AM
What format are these files in? and is this supposed to help with mis-fire's and random blinky-flashy? Thats the issues I'm having on a 256ch olsen 595 (4 board) setup.

I have NOT taken down my lights, in hopes to trouble shoot this NOW, before next year.

THANKS.
A lot of people use the software from PCBExpress I think. These may be in that format. People should say in their email what format the files are. Perhaps downloading them and looking at them with a text editor may tell something as well.

The idea is to clean up the signal from the PC with the intent to eliminate the random mis-fires. There are many issue that cause this though. You only need a little noise on the data lines for extra lines to get turned on.
The big deal with some think like 256 channels is without some kind of delay/amplification you can start to run in to fan out issues with the clock line. You got like 32 chips hanging off of the same clock in this case, and if there is any distance between the boards, this can add up. Also there can be slowing down of the edges of the clocks due to charge up time of the whole circuit. These effects can are generally small, but they can add up.
Some people have a circuit that runs great, some don't.
I was just responding on another thread about a delay to the 595 plugin to attempt to get the circuits to settle before clicking them on/off. This was an option on the 1.1 plugin, but it disappeared on the 2.0 plugin. Maybe it needs to return , just to see if that helps in these cases.
Tony M.

dnesci
01-13-2009, 10:31 AM
What format are these files in?


The are in Express PCB files format. You can get the software for free by going to:

http://www.expresspcb.com/ExpressPCBHtm/Free_cad_software.htm

Don

A Marchini
01-13-2009, 11:26 AM
The are in Express PCB files format. You can get the software for free by going to:

http://www.expresspcb.com/ExpressPCBHtm/Free_cad_software.htm

Don

Oops, should have Googled it before messing up the name and making it PCBExpress.

Tony M.

Cburg
01-13-2009, 01:20 PM
I think the issues were people trying too many variables at the same time and once something worked not really going back to find out why an output driver didn't help.

In the end I guess it doesn't matter as long as there is blinky-flashy in the end.

Tony M.

I agree with you 100%, I know that is just what happen to me 2 years ago. I designed an 80 channel 595 to go under my Mega tree about 80ft from my computer. When I had problems, I tried all sorts of things. Due to the time crunch I did not document anything and like most I stopped when I got something working. I was not sure just what the problem was nor just what fixed it.

This year a again had some issues when I added a (Brien Design) 64 Channel controller ahead of the 80 channel board. Due to health issues and again time, I did not find the problems.

I guess I do not agree with your last part of your statement, I would like to go back now and find a cure. Maybe there is a way for us to step our way though this and try to keep good records.

Some ideas I recall are;
1) paying more attention to just what twisted pair is used for what on the data line.
2) Maybe there is a sort of termination that is needed at the end of the data chain like in a DXM line or the old 10Base-2 lines
3) maybe there is a way to either square up(recondition) the clock signal at each board or re-send a new clock signal on to the next board.
4) maybe something like a booster between the computer and the first controller could increase the voltage (??) to push the signal down the line.

These are just some thoughts from a person that is not an expert but one who only has enough knowledge to be dangerous! :!: