Data loggers...

silent wolfsilent wolf Solar Expert Posts: 92 ✭✭✭✭
I would like to start to say hello to the people of this forum! The reason I have come to this forum is to see information on data loggers. I have a small setup, for a research project, and I need a data logger. This data logger can be hooked up to a computer 24/7 if needed. I need to measure a minimum of 75 watts, so say around 4.5 amps, and 25 volts. I have 5 solar panels to measure from. And I also need a separate data logger for temperature or it can be the same. I am on a tight budget, but also want a quality data logger. Thanks for the help, please post here if you need any more information.
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Comments

  • n3qikn3qik Solar Expert Posts: 741 ✭✭
    Re: Data loggers...

    Look at this:

    http://www.microdaq.com/lascar/index.php

    Post how much you are willing to spend, there are better systems, but cost more.
  • Dave AngeliniDave Angelini Solar Expert Posts: 5,087 ✭✭✭✭✭
    Re: Data loggers...

    Check the "Dilbert company" Omega.
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail [email protected]

  • silent wolfsilent wolf Solar Expert Posts: 92 ✭✭✭✭
    Re: Data loggers...

    Well, I would like to spend under $500 or so. I am mostly looking for current and voltage more than anything. Also, the computer will be somwhere else, at least 50 feet away.
  • n3qikn3qik Solar Expert Posts: 741 ✭✭
    Re: Data loggers...

    Look at this, one member has this.

    http://welserver.com/intro.htm

    Also look at this site, This is where I purchase my stuff from.

    http://www.bb-elec.com/productcat.asp?topLevelid=4
  • silent wolfsilent wolf Solar Expert Posts: 92 ✭✭✭✭
    Re: Data loggers...

    Ok, well it needs to collect volts and current at the same time, most of those either do on or the other a different times. Can you just send me a link to certain ones you would recommend? instead of sending me just the webpage.
  • mikeomikeo Solar Expert Posts: 386 ✭✭✭
    Re: Data loggers...
    Ok, well it needs to collect volts and current at the same time
    
    Actually you just need to measure voltage in both cases. The problem is that to measure current, you just measure the voltage drop across a calibrated shunt. In your case, a 100 amp, 100 mv shunt would do what you want it to do. The voltage is just scaled from 0 to 100 mv = 0 to 100 amps. The next problem is that this needs special amplifier with a gain of about 150 to measure it with a typical data logger channel. There are special chips just for this, but I haven't found a data logger with the chip built in. Maybe others will chime in with a solution.
  • silent wolfsilent wolf Solar Expert Posts: 92 ✭✭✭✭
    Re: Data loggers...

    Ok, well the only reason for volts and current is so I can measure the watts, is if there is a data logger that does that already that would make it a lot easier.
  • GreenerPowerGreenerPower Solar Expert Posts: 264 ✭✭✭✭✭✭
    Re: Data loggers...

    Take a look at these to see if any suits your needs.

    http://www.dataq.com/
    http://www.mccdaq.com/

    Like MikeO said, you really to measure voltage across a shunt for amps. If there isn't a low noise amp module/probe, you might need to build one from discrete low noise op-amps.

    GP
  • silent wolfsilent wolf Solar Expert Posts: 92 ✭✭✭✭
    Re: Data loggers...

    I do not understand these "shunt" volts.... How do they work?
  • silent wolfsilent wolf Solar Expert Posts: 92 ✭✭✭✭
  • a0128958a0128958 Solar Expert Posts: 316 ✭✭✭
    Re: Data loggers...

    I'm at least one member here with a solar performance and energy monitoring logging system using the WEL. My system's at http://welserver.com/WEL0043/ .

    If I were to use a WEL to accomplish what you want to do, it would be straightforward and not difficult. Unfortunately, though, while accuracy, reliability, and real-time access to charts and data are all easily accounted for, it's not doable for your $500 budget. Some other less expensive system would be needed.

    Noting that you don't need separate voltage and current measurements on the DC and AC sides of the inverter, and instead can use power measurements, then one alternative is to obtain an interface board for your inverter, and then log the power data from the inverter interface.

    Using a WEL, I would use a Continental Controls WattNode unit with appropriate current transformers on the AC side. Very accurate, very reliable, with high resolution, and logging every 60 seconds to an external location that's included in the price of the WEL (i.e., no local computer needing hook up to).

    Power on the DC side of the inverter would have to be measured with current and voltage sensors, and then use the WEL's arithmetic capabilities to multiply the two together for power. CR Magnetics makes DC Current and Voltage sensors. The DC Current sensors are similar to AC current transformers - no shunt required. Click here for the DC voltage sensor.

    While none of this CR Magnetics stuff is inexpensive, the project is certainly doable, as presented, BTW. Plus, you'd need a power supply for the sensors.

    Hope this helps.

    Best regards,

    Bill
  • GreenerPowerGreenerPower Solar Expert Posts: 264 ✭✭✭✭✭✭
    Re: Data loggers...
    I do not understand these "shunt" volts.... How do they work?
    It is basically a very low Ohm resistor so that it won't affect your circuit to insert in series to measure amps. A 100mV/100A shunt is a 1 mili-Ohm resistor - 1A current would cause 1mV across it. So, we measure the voltage drop across the shunt to calculate the current in that circuit. At 100A, only 0.1V drop so that it won't affect whatever you are measuring.
    That would certainly do but probably over-killed unless you are planning for other usage down the road. The USB-1208 would do. You still need a low-noise op-amp to scale 100mV to, say 24V (the max DC Volt the module can measure) to measure current.
    GP
  • mikeomikeo Solar Expert Posts: 386 ✭✭✭
    Re: Data loggers...

    You can put these two products together and calculate power from 2 separate devices:

    http://pdfdata.datasheetsite.com/pdf1/TI/INA198.pdf

    http://www.dataq.com/products/startkit/di158.htm

    You should come up with something for less than $200 dollars if you are good with electrical circuits
  • newenergynewenergy Solar Expert Posts: 291 ✭✭✭✭✭✭
    Re: Data loggers...

    I haven't used this, but Google PowerMeter:

    http://www.google.com/powermeter/about/index.html

    Works with this in the US:

    http://www.theenergydetective.com/index.html


    ---

    Anyone use this?
  • a0128958a0128958 Solar Expert Posts: 316 ✭✭✭
    Re: Data loggers...

    I know some people who are using TED combined with Google Power Meter. They report the products work well and as advertised. Sounds like this is a good monitoring solution if the feature set fit your needs.

    Best regards,

    Bill
  • silent wolfsilent wolf Solar Expert Posts: 92 ✭✭✭✭
    Re: Data loggers...

    Ok, that will not work, as I said before I need all the data. I need it recorded, and saved, and also need it for about 7 months. I can just read it and write it down, I need to go to work. And my system that my project is is only going to be about 400 watts total.
  • silent wolfsilent wolf Solar Expert Posts: 92 ✭✭✭✭
    Re: Data loggers...

    Ok Sorry for the mishap!

    Ok, well I have been on so many websites/ forum/ sales site. And I am really confused. Can you please help me out now. I need to hook up 5 solar panels and need to measure the voltage, and current of each one. They are not linked together at all, I am comparing the volts. I wish not to measure anything, or use voltage spliters or anything but a data logger. I need it to at least to record it every hour, and save it, and it can be plugged into a computer 24/7 if thats a issue, And can be indoors, and has a power source at all times.

    If you would like to help me, please post up data loggers with the appropriate sensors with it.

    Thanks a lot, at this point I would like to spend under $600.
    THANK YOU AGAIN! And also for the people that helped me out already!!!!
  • a0128958a0128958 Solar Expert Posts: 316 ✭✭✭
    Re: Data loggers...

    Is this an accurate summary of your project set up:
    1. Five panels, each connected to an inverter, running simultaneously with the same lighting illumination.
    2. Panels are outdoors?
    3. Instrumentation can be indoors. 120 VAC is available.
    4. Internet connection available?

    And is this an accurate summary of your instrumentation needs:
    1. DC voltage (around 25 V) and DC current (around 4.5 A) for each panel, simultaneously measured (i.e., 10 measurements).
    2. Temperature of each panel (i.e., 5 measurements).
    3. Sample frequency of at least once per hour.
    4. Data storage capability for at least 7 months.
    5. 24 x 7 unattended data measuring needed.
    6. Battery backup to the instrumentation system so that measurements are not missed.
    7. Good accuracy required (but not precision).

    Best regards,

    Bill
  • silent wolfsilent wolf Solar Expert Posts: 92 ✭✭✭✭
    Re: Data loggers...
    a0128958 wrote: »
    Is this an accurate summary of your project set up:
    1. Five panels, each connected to an inverter, running simultaneously with the same lighting illumination.
    2. Panels are outdoors?
    3. Instrumentation can be indoors. 120 VAC is available.
    4. Internet connection available?

    And is this an accurate summary of your instrumentation needs:
    1. DC voltage (around 25 V) and DC current (around 4.5 A) for each panel, simultaneously measured (i.e., 10 measurements).
    2. Temperature of each panel (i.e., 5 measurements).
    3. Sample frequency of at least once per hour.
    4. Data storage capability for at least 7 months.
    5. 24 x 7 unattended data measuring needed.
    6. Battery backup to the instrumentation system so that measurements are not missed.
    7. Good accuracy required (but not precision).

    Best regards,

    Bill

    Project:

    5 panels

    Panels are outdoors

    Panels are not connected to a inverter, but can be if needed

    Internet is available

    Near 120 output

    Instrument can be indoors


    Instrument needed:

    I can take the data off the machine weekly, or every other day

    Good accuracy required

    Battery back up (optional, not required)

    Temperature (This could be a separate unit)

    DC voltage (around 25 V) and DC current (around 4.5 A) for each panel, simultaneously measured




    Thanks,
    Kevin
  • a0128958a0128958 Solar Expert Posts: 316 ✭✭✭
    Re: Data loggers...

    Kevin, if you don't have inverters connected to the panels, what load will be connected to the panels?

    Best regards,

    Bill
  • silent wolfsilent wolf Solar Expert Posts: 92 ✭✭✭✭
    Re: Data loggers...

    I have resistors. Also I can get a inverter as well. I had a multi meter also that had resistors in it to measure current. I do not know if they make data loggers with resistors in it.
  • a0128958a0128958 Solar Expert Posts: 316 ✭✭✭
    Re: Data loggers...

    You've got a good number of 75 watt resistors? (i.e., lots of heat)

    Best regards,

    Bill
  • silent wolfsilent wolf Solar Expert Posts: 92 ✭✭✭✭
    Re: Data loggers...

    Ya, from work, they have aluminum heat sinks on it, but I will probably get a inverter though.
  • n3qikn3qik Solar Expert Posts: 741 ✭✭
    Re: Data loggers...

    Going out on a limb here, but are you using 5 setups to find/log best place to put a future array??
  • silent wolfsilent wolf Solar Expert Posts: 92 ✭✭✭✭
    Re: Data loggers...

    No, Not at all. My research project is to cool solar panels, and I water cooled solar panels.... Results are outstanding, I want to test during the summer and thats why I need the data loggers. They will be all withing a 5 foot radius of each other.
  • silent wolfsilent wolf Solar Expert Posts: 92 ✭✭✭✭
    Re: Data loggers...

    I have 5 designs, and want to patent my work. They may be for sale next year.
  • mikeomikeo Solar Expert Posts: 386 ✭✭✭
    Re: Data loggers...
    I have 5 designs,
    So you want to measure all 5 panels independently and simultaneously? That will require a 10 channel data acquisition board with appropriate sensors. Is that what you are asking for? And all for under $600?
  • silent wolfsilent wolf Solar Expert Posts: 92 ✭✭✭✭
    Re: Data loggers...
    mikeo wrote: »
    So you want to measure all 5 panels independently and simultaneously? That will require a 10 channel data acquisition board with appropriate sensors. Is that what you are asking for? And all for under $600?



    Well ya, I know they are really expensive... But ya. If you cannot find one under $600 Can you at least post the cheapest you find? I am considering using a voltage splitter now that I see it will cost so much.
  • a0128958a0128958 Solar Expert Posts: 316 ✭✭✭
    Re: Data loggers...

    I looked at this for a little while, knowing that the WEL satisfies all of your non-sensor related requirements and it's inexpensive ($385).

    But connecting 5 channels of 0-25 VDC and another 5 channels of 0-5 A to a WEL is expensive - way over your $600 budget.

    For example, a Hall Effect DC Current sensor (simply slips around the wire - no shunts to mess with), with a 4-20 ma output (compatible with the WEL) is by itself a $140 item. And 0 - 50 VDC to 4-20 ma sensors are similarly priced. And since the WEL only provides two 4-20 ma inputs, you'd need multiple WEL units.

    While this accomplishes the objective of everything being off-the-shelf, accurate, reliable, etc., it doesn't make sense from an expense point of view.

    You may want to look at Campbell Scientific Data Acquasition Systems (DAS). For example the Solar Decathlon competition that occurs every other year specifies and requires this company for all instrumentation of the solar panels (and everything else). I think expense, though, will be a problem too with this alternative.

    Hopefully someone else here can come up with a low cost solution. I just don't have a lot of exposure to DAS outside of the WEL unit.

    Good luck!

    Best regards,

    Bill
  • mikeomikeo Solar Expert Posts: 386 ✭✭✭
    Re: Data loggers...
    I know they are really expensive
    To do what you want you may have to roll your own. Look on EBAY there are several 12 bit and 16 bit DAQ's in the $150 dollar range with 16 input channels. Some are ISA boards so you would need to dredge up an older computer for a data acquisition platform( should be free for the taking). Then you would need qty 5 100 amp or smaller shunts, which should cost less then $100 for all 5 shunts, and 5 shunt amplifiers from Texas Instruments or other source which should cost less than $40. Since most DAQ units have a range from -10 to + 10 volts you would need some 1% precision resistors for voltage dividers to brings the panel voltages into range of the DAQ board. Some basic circuit wiring, some BASIC or C programming and you would have what you want for less then $500 and some of your labor. I expect you will pay several thousand dollars to get a ready made package to do what you want. Do you have a friend that could put the system together for you if you don't think you can?
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