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1  Using Arduino / Project Guidance / Re: Logging pulses from meters on: March 13, 2011, 05:34:16 pm
That makes sense! Thanks, I'll give that a try.

As for your project, if you're writing to an SD card, I wonder if you could use one of those Eye-Fi cards that are essentially SD with built in WiFi?

I haven't even began researching the communication aspects of this, but if I do find something that works for me, I'll be sure to let you know.

Thanks for the response!
John
2  Using Arduino / Project Guidance / Re: Logging pulses from meters on: March 09, 2011, 01:19:49 pm
Hey guys, any advice on the last post?
3  Using Arduino / Project Guidance / Re: Logging 12VDC pulses from meters on: February 23, 2011, 07:55:03 pm
Sorry, I was away for nearly a month. I'm back now.

So, I emailed the manufacturer and asked them exactly how these isolated outputs worked. They replied with the following:

Quote
The isolated outputs which are 10, 100, 1000, they are the open collector of the photo-transistor.  The isolated com terminal is the emitter of the photo-transistor.

All the isolated outputs are 50% duty cycle.

10 is 10Wh per pulse.
100 is 100Wh per pulse.
1000 is 1000Wh per pulse.

Now, obviously not an expert at this stuff, but to me a photo-transistor sounds like it performs the same job as an opto-isolator. Is this correct? Would using these outputs be easier than adding an opto-isolator to the 12V counter output? And if so, how would I go about feeding this into an Arduino?

Thanks guys! Once again, I really appreciate all your input.
4  Using Arduino / Project Guidance / Re: Logging 12VDC pulses from meters on: January 27, 2011, 09:08:18 pm
Quote
I thought I might be able to cheap out since I'll have to buy ~15 of these
I would expect to pay well under US$ 1 each, so it doesn't seem like a big budget item.

Oh really? The ones I've been looking at are $15to$20 $14: http://www.opto22.com/site/pr_details.aspx?cid=4&item=IDC5D
5  Using Arduino / Project Guidance / Re: Logging 12VDC pulses from meters on: January 27, 2011, 08:54:52 pm
Sorry, I've created some confusion by leaving out some important details from the original thread (see link at top).

In summary: At first I was only aware of the 12V counters which are currently hooked up to these meters. The idea was to read the pulses off these lines. These counters do not have a common ground.

Now that I'm gotten my hands on the meters and the manual that goes with them, I've discovered there are 3 additional outputs (the ones I've described above).

I decided to keep the original thread title for consistency. Again, sorry for the confusion.

Quote
Regardless of what the voltage is (5V or 12V or whatever), Opto-isolators are VERY STRONGLY recommended, regardless of what response you get (if any) from the vendor. I would absolutely never try this without good isolation!

Thanks! I thought I might be able to cheap out since I'll have to buy ~15 of these, but I'll take your (and AltairLabs's) advice.

Quote
Note further that depending on how much power we are talking about, even the 10 Wh/P output may be very slow. You will need to write Arduino code that can handle a slow input wave speed.

Yeah, it sounds like the output will be pretty slow, especially since the loads on these  meters aren't going to be a whole lot (camp sites). Thanks for the heads up.

So.. it sounds like I have some opto-isolator shopping to do!
6  Using Arduino / Project Guidance / Logging pulses from meters on: January 27, 2011, 08:02:18 pm
Continuing from the old thread ( http://arduino.cc/forum/index.php/topic,22640.0.html )

Alright, so I'm back smiley

A few things:

- The counters don't appear to share a common ground.
- I'm pretty comfortable with soldering, just not very comfortable at creating circuit designs smiley As long as I have smart people like you to help me through, "rolling my own" opto-isolators sounds like something I can probably handle.
- These meters appear to have additional outputs that sound pretty promising. They are:
   
   - "10, Isolated Output (10 Wh/P, Kh = 10)"
   Definition: Isolated pulse output: 5 watthours on, 5 watthours off, reference to ISOL COM
   NOT TO BE USED FOR FIELD WIRING

   - "100, Isolated Output (100 Wh/P. Kh = 100)"
   Definition: Isolated pulse output: 50 watthours on, 50 watthours off, reference to ISOL COM

   - "1000, Isolated Output (1 kWh/P, Kh = 1000)"
   Definition: Isolated pulse output: 500 watthours on, 500 watthours off, reference to ISOL COM

   - "ISOL COM"
   Definition: Isolated common for 10/100/1000 isolated outputs

Now, this sounds promising! I've emailed the people who make this meter to ask them what voltage the isolated outputs are giving out. If it's 5V would that mean there is no need for opto-isolators?
7  Forum 2005-2010 (read only) / Interfacing / Re: Logging 12VDC pulses from meters on: January 23, 2011, 01:35:03 pm
Wow, thanks for the quick and informative replies.

I'll try to find out more about the meters when I have access to them again.

As for the duration of the pulses, I'm going to guess that they are 0.1s since the counters claim they work at 10Hz.. EDIT: It sounds like there are multiple counter outputs on these meters (10 kWh, 100 kWh, 1000 kWh), that give different levels of accuracy. I'll see if I can find more about these pulses and get back to you.

Thanks again for the help.
8  Forum 2005-2010 (read only) / Interfacing / Logging 12VDC pulses from meters on: January 23, 2011, 11:24:58 am
I'll start by saying that I have no idea what I'm doing, and I'm hoping you guys can give me some direction. I'm a software developer but have minimal experience with electronics.

My father runs a small Campground and has 15 individual kWh meters (luckily contained within the same enclosure) that are each hooked their own electromechanical counter:

> Kubler K46 Electromechanical Micro-Counter @ 10 Hz count frequency

According to the documentation from the meters, the voltage into these counters is 12VDC.

Right now my father has to go and note the values of each of the meters at 3 points in the day... every day. He has never complained, but I feel this can be somehow automated.

Now my question is, what kind of board would I need to accept these pulses as input for logging purposes? It seems 12V is within the input range of the Duemilanove, so would this be able to do the job? If so, how many pins on the board could I use for this pupose? 14?

Sorry for the amateur questions, and would appreciate any suggestions/direction I can get smiley Thanks!
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