Datalogger?

[zeke 693]

Hi Guys,

 

I just thought of another product idea. Tell me what you think?

 

I am preparing lab tests for a new power supply design. I am trying to figure out how to test 15 power supplies simultaneously inside of an environmental chamber.

 

I have to measure input voltage & current and output voltage & current of each unit all the while varying the temperature between -40'C and +85'C. In addition to that, I have to vary the input voltage to each unit between 18 and 36 VDC. This whole process is called 4-Corner Testing.

 

The challenge is in collecting the measurements on 15 units while they are at the temperature extremes.

 

The old school method would be to hook up wires to everything to be measured and string them outside of the chamber, seal off the hole with thick foam and tape, then measure each test point individually by hooking it up to the voltage and ammeters. This is extremely tedious and time intensive.

 

Here's my idea: Create a tiny datalogger that will measure and save five analog measurements. It would then transfer that data to another computer somehow.

 

I thought of adapting the RF2500T. I would have to design configurable input signal conditioning so they could adapt to different voltage ranges.

 

I think the 22x4 has 12 A2D channels, if I read the datasheet correctly. They're numbered non-consecutively. I don't know if they're worth the effort at $20 a piece though. :?

 

 

If the cost is minimal then these dataloggers could be mass produced.

It would be nice if they all connected to one comm buss so that the snake of wires would be minimized.

The measurements would have to be reasonably accurate within a couple of decimal places.

The devices would have to be able to survive repeated temperature cycling because that's where they will live.

 

I spent a sleepless hour last night watching my imagination run wild with this idea. I just couldn't shut my mind off. So, it seems to me that the idea could have some merit in certain circumstances.

 

Does the idea hold water?

Is there something out there already?

Is it a crowded market segment?

 

What do you all think?

[zeke 693]

I guess I scared everyone away, eh?

 

Take a look at this datasheet. It's an all in one high side current sensor that could be used to measure the [18..36]Vdc input voltage and input current.

 

If ti.com ever comes back, I could check out the INA170 device to see if it would work for measuring the output voltages and current.

[bluehash 1,581]

If you can provide 12 bits of ADC resolution, that's good. Surely, there are sensors on the market that do this, but they are very expensive. But not everyone does extreme temperature testing. Having it wireless is even better, but wireless signals is an additional interference one has to consider.

You should do a proof of concept and then go from there.

[zeke 693]

It turns out that I'm late to this party.

 

I did some googling and http://www.NI.com is apparently the funkytown of tiny dataloggers.

 

For example, here is a USB device with 8 analog inputs and 2 analog outputs for ~$200.

 

If I were to pursue this then the PC side data collection software is still a mystery to me right now. It has to come from somewhere.

[bluehash 1,581]

did some googling and http://www.NI.com is apparently the funkytown of tiny dataloggers.

Well, on the other hand, Labview costs thousands. But you can distribute the runtime to your clients for free.

[zeke 693]

You've got me thinking about an interesting idea.

 

I stumbled across Adobe Flex and it got me thinking that I could use it for a cross platform runtime.

 

I don't know if it can obtain access to the USB/Serial ports. I'll have to check that out.

 

Here's a demo program called TourdeFlex that shows off a lot of what it can do.

 

Apparently, you can get AIR to talk to a serial port but you have to use a proxy program since AIR talks TCP ports only. Check out this article for more info.

[zeke 693]

Holy Mackerel! :shock:

 

I just realized that there's a connection between the S2E module, the data logger and the AIR/Flex application ideas.

 

The data logger has a serial port on it. It connects to the S2E module. The S2E module presents a TCP port to the AIR/Flex application. The AIR/Flex application communicates to the data logger and it doesn't even know it's going through an S2E module.

 

Hmmmmmm..... This looking like a complex project. 8-)

 

So, does anyone out there think I'm insane yet?

[bluehash 1,581]

I think its a great idea. The datalogger has no idea it is on an ethernet line.