60Hz noise making it's way into my test

Is that 0 to -25 or 0 to +25 volts?

Does this mean that you are reading the voltage with an analog input, and finding the edges in that data?

Is one side of the supply connected to signal ground of your data acquisition board?

Hi John,

I would like to reply inline, but I'm using the google website for this and it won't show me the orginal message. Apologies for my bad formatting.

To answer your questions:

"Is that 0 to -25 or 0 to +25 volts?"

"Does this mean that you are reading the voltage with an analog input, and finding the edges in that data?" Yes, this is exactly what I'm doing

"Is one side of the supply connected to signal ground of your data acquisition board?" This I'm not sure about. I do run the supply through the board to check current draw (cheap short check), but I'm not sure if I'm using signal ground. I don't have it in front of me at this time, but I will look into that. Sounds promising.

Thank you for your post!

-Steve

THis is also posted from Google Grpups. You have to select "Show options" at the top, instead "Reply" at the bottom, then "Reply" at the top, to have the previous post quoted. It is not well explained on the site.

Okay. What voltage swing does the counter input need?

:0)

"input low voltage: 0.8v max" "input high voltage: 2.0v min"

I'm figuring that this counter wants a DC signal, so I would need to rectify the AC square wave (from what I have read and been told).

No, I am wrong here. please ignore this.

I think this means that any voltage below .8 volts (but above zero) will be interpreted as a logic low, and any voltage above 2 volts (and probably below 5) will be interpreted as a logic high. Any voltage between .8 and 2 is not guaranteed to be interpreted as one state or the other.

I think you might be able to just divide the 0 to +25 volt wave to a something like a 0 to +5 volt amplitude with to resistors and connected that smaller signal directly to the counter. A pair that might work would be 10k to the 25 volt signal, and 2.4k to ground. The junction of those two resistors should provide a 0 to +4.8 volt signal.

I really want to do that :0) We had hired a consultant to make a basic application to show how to interface with the acquisition hardware. I could have figured it out, but decided that it would be more efficient to pay someone to "jump start" things. Anyway, long story short, for a reason that I can't remember at this time, the consultant said he couldn't use the counter. He told us we would need to calculate it based on the analog voltage values read in.

We are squeezed for time so accepted this. So as of this writing, I'm just trying to get the system that he delivered working and in use. Then, when I have a little time, I want to do exactly what you said, divide things way down and try and use the counter, which I would hope is much more accurate that counting analog edges like I am now.

I will look into the ground issue you had mentioned. Thanks for reassuring my suspicions that the counter is a good way to go or atleast worth another look.

-Steve

Hi, Steve. The trace and your description indicate that you're probably getting 120Hz ripple on your wall wart power supply -- that makes it a good candidate for replacement. If you can find the spec on the wall wart (usually on the back of the supply, on the side where the plug is), that will give you a good idea where to start. Possibly your wall wart is/was a 5VDC regulated power supply? It kind of looks like the input cap in the wall wart went south and opened up. Replacements are commercially available at less than $20 for 5VDC regulated (make sure it's a linear regulated s3upply) at 1 amp.

Jameco sells their P/N 168605CB 5V regulated supply for $12.55 -- buy

If it worked well before, you should be able to get it working again. Unfortunately, you didn't include any more information, so I guess it would be tough to be more specific. Sorry about that. Feel free to post again with as much information as you want.

Good luck Chris

Yes, it will.

Don't click the "Reply" link at the bottom of the post. Look up at the top of the post, and click the "Show Options" link. Then, click _that_ "Reply" link (toward the left of the list of options). This will quote context.

Then, snip irrelevant material, scroll to the bottom of the post, and put your reply at the bottom. This maintains the natural order of reading a thread.

Good Luck! Rich

This was supposed to be attributed to "Sandbox Moderator", not "Pig Bladder".

On Wed, 05 Apr 2006 15:08:19 -0700, SklettTheNewb wrote: ...

If it isn't working and in use, his job isn't done.

If you've already paid the consultant, and he didn't get the job done, then you're a fool and he's a swindler.