Literature on data loggers - Page 1
Forum section: electronics / general

author: Slobodan
author_rank: Regular Contributor
timestamp: March 03, 2013, 04:41:36 pm
content: I need to write a paper on data loggers. I can't find sufficient literature/documentation on them. Nothing that I have found is more extensive than the wikipedia article. So if you have anything that can help me, please post a links to that.

author: Unknown
author_rank: Unknown
timestamp: March 03, 2013, 10:14:56 pm
content: You are faced with a considerable problem; time has moved-on, and documentation on mechanical loggersas you have found out, is extremely thin on the web.This will not help, but may do some-thing for you:http://www.vaisala.com/Vaisala%20Documents/White%20Papers/lsh-Dataloggers-vs-chart-recorders.pdfHowever you might find some useful information on these Mechanical Recorders via this site:http://www.directindustry.com/industrial-manufacturer/chart-recorder-75710.htmlAnd Here:http://www.wastechengineering.com/newsletters/mail49_recorders.htmGood luck...

author: Slobodan
author_rank: Regular Contributor
timestamp: March 04, 2013, 08:01:34 am
content: Thanks, but literature on mechanical data loggers will only cover the "history" part of the paper. I have already wrote something about tachometers, event recorders and flight data recorders in the "history" section. But what I really need is literature on modern electronic data loggers. I have never designed one, so I can't just write all of that from my head.

author: Slobodan
author_rank: Regular Contributor
timestamp: March 06, 2013, 07:45:41 am
content: Nothing?

author: Rerouter
author_rank: Super Contributor
timestamp: March 06, 2013, 08:44:47 am
content: to this subject i may be one of your allies, i not only work with and fit vehicle monitoring devices, but also have to repair and calibrate them for work, equally i see a good number of industrial plant units via instrumentation,so if you want a much larger starting point look up "tachographs" a speed / rpm chart recorder, in NSW they are legally required for transit vehicles "TV-xxxx" plates, most buses and trucks manufactured in europe will generally come with one pre-installed, either as a separate unit mounted in the dash, or acting as the main speedometer / tachometer, they have a stylus for speed / tacho, but also a stylus that follows a triangle wave pattern for traversed distance, and a lower sytlus that scores a mark every 200m, that way if one of the styluses wher to be bent or inhibited the remaining data could be worked out from the other 2, they use wax coated charts, and the stylus etches a fine line revealing the black backing colour giving the impression of a fine black line,next up would be the pen plotters, these are either flatbed or cicrular and were only in the past 2 decades popular in instrumentation before becoming obsolete, effectively a motor or clock-spring slowly wound the chart around at a fixed rate and recorded the input value in most cases taking a voltage signal of 1-5V or 4-20mA and making it represent a span on the chart,these are still in use in some businesses for units that can still have either the wax charts are made for the model, or they have been able to refill the ink storage depending on how they are built,and then onto the modern era, as tech became cheaper and some of the circa 1950/1960 units stopped having charts or ink or spare parts supplied, other companies began pushing for newer electronic units to be developed, and as they are to function as both a real time display and a recording device in most cases it resulted in some very interesting designs, though i will focus on one of the higher end circa early 1980's units i have had to play around with recently, firstly, it has both an internal storage element and a floppy disk drive built into the unit, allowing for long term logging like is expected with most of these systems, they store the data be it a chart a floppy or a file somewhere, so if there is an issue they can follow it back up,the device has a 5 pin array that makes up its input selections, from memory supporting, voltages 0-200mV (pretty much all thermocouples with internal scaling factors) 1-5V (standard signal) resistance, e.g. a PT100, a resistance based temperature probe, 4-20mA and a few other odd ones, e.g. +-1V with 3 banks of those inputs, with one interesting feature in the current input, it uses a current mirror to maintain the smallest possible voltage drop on the external signal, which is rare to see even in fairly modern units, (generally use a 250 ohm resistor, 20mA x250 = 5V drop at full signal)internally the newer unit supports scaling, custom ranging, and basic math to apply custom units to the percentage of the input, e.g. 44% = 213 beers per minute,it also allows you to set dampening and integral responses on the input signal, allowing noise and spiking to be ignored, etc, something rare to see with the mechanical units, generally requiring a modification to the measuring element or for it to have the options available, (not common in the 1980's)equally the device has a fixed sampling speed of about 1 second, however you can set the "chart feed rate" (remembering this was new at the time) for how often it actually stores a sample,and as a quirky feature as it had to compete being new tech at the time, it also has a rather pronounced feature that calculates how much it has saved in ink and charts through using it,the very new units get similar to digital storage oscilloscopes, for more math has been added, network, usb and memory card support added, even in some units some control elements added as they combine with controllers being most of the tech required is pretty much the same, though they generally get re-termed recording controller then,ask any questions you may have, i might have more to chip in

author: Slobodan
author_rank: Regular Contributor
timestamp: March 06, 2013, 10:04:31 am
content: Thank you very much. This will help me to fill in the gaps in the history section of the paper.But, that section is practicly complete. What I was looking to find is literature on general purpose digital data loggers, that are in use today.

author: sub
author_rank: Regular Contributor
timestamp: March 06, 2013, 10:21:43 am
content: Have a look at some of Agilent's app notes on the subject. They will most likely tell you about (for example) the switching matrices and whatnot that are used in their devices.

author: Slobodan
author_rank: Regular Contributor
timestamp: March 14, 2013, 05:16:23 pm
content: I am still 5 pages short...

author: ftransform
author_rank: Frequent Contributor
timestamp: March 14, 2013, 06:12:32 pm
content: sounds like you need bigger pictures, font, spacing, margins and some good old rambling

author: andybdjuk
author_rank: Newbie
timestamp: March 14, 2013, 06:38:54 pm
content: HiNot sure if this helps but application notes from companies like below may help you on current software data logging techniquewww.daqconnect.comwww.azeotech.com/daqfactory.phpwww.ni.com/labviewAndy

author: Slobodan
author_rank: Regular Contributor
timestamp: March 15, 2013, 08:31:40 am
content: Quote from: ftransform on March 14, 2013, 06:12:32 pmUnfortunately, paper like that would not be acceptable. Pictures don't count as pages, only text.Quote from: andybdjuk on March 14, 2013, 06:38:54 pmThanks, maybe it will help me a bit.