Sign in to follow this  
Followers 0
Div_by_zero

Need equipment to log DC voltage for weeks, months

6 posts in this topic

I need to log a relatively small (~3.0V) DC voltage on a PCB. I'm thinking about getting a Fluke 289 which would do the job, I think, except it's battery powered and it would die well before my test (up to a month) was over. I need to log the voltage 24 times a day. I was thinking about using a PLC, but wasn't really sure what type of input module would allow me to do this. Perhaps some other piece of plug-in standalone equipment? I have an energy logger, but it's line powered and really geared towards mains work, not this sort of thing. Please advise, thanks! Edited by Div_by_zero

Share this post


Link to post
Share on other sites
need more info... for something on the bench, you can use PLC (powered from outlet). just need analog input card. standard analog cards include ranges 0-5V and 0-10V. depending on PLC resolution will be 8, 10, 12 or 16bit If you need something to be used on a battery power I would consider embedded solution using microcontroller. there are tons of development kits and they are low power - can run for months on battery (or years depending on battery ). one just need to check required resolution for analog input and memory needed to store the data. 30days * 24 samples is really not much data. many development kits are very powerful (16 or 32bit core) but not always easy to get familiar with. one of simplest to get familiar with is arduino - which has 10-bit ADC, arduino due has 12bit etc: http://arduino.cc/en...gReadResolution there are tons of 16-24bit ADC if you want something that really rocks. many are available as modules: http://www.adafruit.com/products/1085

Share this post


Link to post
Share on other sites
What I am reading is clock battery voltage on a PCB. So the battery will be its own source of voltage. I never used an analog in card in such a manner but I guess it will work?

Share this post


Link to post
Share on other sites
Is this a button battery? If so, you should consider the impedance of your analog input. On a period of a month, it could influence your battery output.

Share this post


Link to post
Share on other sites
It's the battery that powers the RTC. Yes, it's a "button" style battery. What I would do is pass one of the test leads through a dry-contact relay, and only close the relay once per hour just long enough to take a test reading. Edited by Div_by_zero

Share this post


Link to post
Share on other sites
yep, if it is a coin cell battery, analog input of a standard MCU (~10k) without conditioning circuitry will drain the battery in a month or so on its own (like CR2032 for example). fortunately it is easy to obtain higher input impedance using voltage follower for example. still no any usable data... till then any suggestion is just a guess, soooo.... try answering following 1. what is your budget ( ) 2. what is your skill / experience 3. what is the type of battery under test 4. what source of power (volts/amps) is available for powering logger 5. what is the environment (moisture, temperature, noise...) 6. what is the expected footprint/weight etc.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0