ADC value Units

On the Original Thoughtstream, for the 5th and 6th bytes that make up the 12 bit ADC value (from the ThoughtStream Interface Software User's Guide), can somebody tell me what units the number is in or some way to convert it to ohms?

thanks,
EM

The conversion for the RS-232 TS is ...
Probe resistance (in Megohms) = (1925 / (12 bit ADC value)) - 0.47

:cheers: Todd

Concerning the software:
What I would really love being able to do with the software is to export every measured value and the time when it was measured into an excel file for further statistical operations.
Although I am not sure if this can somehow be accomplished with the current TS software, I think it could easily be implemented in a future version, don't you think?


Thanks a lot,
Thomas

Hi Thomas;

I know you can save the session - have you checked to see what sort of format the data is in?

-Andy.

Hi Andy,

my reseller here in Germany just sent me an example txt. file presumably from a TS USB where the interface software stores its saved data. It looks like this:

7484,60991
7490,60991
7495,60991
7499,60991.2
7503,60991.2
7505,60991.2
7509,60991.2
7512,60991.41
7517,60991.41
7521,60991.41
7525,60991.41
7530,60991.61
7534,60991.61
7539,60991.61
7543,60991.61
7548,60991.81
7552,60991.81
7557,60991.81
7559,60991.81
7563,60992.02
7566,60992.02
7570,60992.02
7574,60992.02
7579,60992.22
7584,60992.22
7588,60992.22
7592,60992.22
7595,60992.42
7598,60992.42
7602,60992.42
7606,60992.42
7610,60992.63
7614,60992.63
7617,60992.63
7618,60992.63
7619,60992.82
7619,60992.82
7620,60992.82
7621,60992.82
7623,60992.82
7624,60993.03

First column is the measured resistance value in kilo-ohm, second column after the comma is the time it was measured in seconds of the day (for example 17 o'clock in the afternoon = 17 hours * 60 minutes * 60 seconds = 61200 seconds).

Ok, so with this, exporting into Excel or any other statistical software is a breeze. The only thing I don't like too much is the format of the measurement time. It could be more precise and starting from zero... well, maybe one can at least edit the starting point to zero seconds oneself.


Thanks,
Thomas

Hi Thomas;

That's good news that it's already in a simple fomat.

I heard that the format may change with the new software. I should hear fairly soon as to what that format will be.

-Andy.

Hi Andy,

now that you mention it :eusa_think: I assume the txt. file was probably from the "old" interface software. Let me know what you can find out regarding the new USB interface software.

Thanks,
Thomas

Here's the poop on the new software:

When you save a session it saves the data in a 'txt' file.
The format of the file is comma delimited with two entries per line.
First entry is the 14 bit probe reading , the second entry is the session time in 100th of seconds.

To convert the 14 bit probe reading to resistance put it in the following equation...
Probe Resistance = (7,700,010,000 / 14 bit probe reading) - 470,000 ohms

Divide the time value by 100 to get the time in seconds

-Andy.

Hi Andy,

thanks for letting me know! :icon_thumleft:

So that means that time measurement starts from 0 seconds with the new software, no matter when the measurement takes place?
Also how many times does the 14 bit probe take readings per second (sorry - per second, not per minute)?


Thanks,
Thomas

Hi Thomas;

The TS USB puts out 20 readings / second.
The record usually starts at 30 which = 0.3 secs.
The reading that is sent is an average of six readings.
The buffer has to fill before the first reading is sent, so that's why the first reading is at 0.3 seconds.

Hope that helps.

-Andy.

@ Andy:

So that means each measurements that is displayed in the interface software is really the average of 6 measurements? And these exact measurements are still saved in the txt. file individually?

Thanks,
Thomas

Quote:

---

Originally Posted by Thomas

So that means each measurements that is displayed in the interface software is really the average of 6 measurements?

---

Yes.

Quote:

---

Originally Posted by Thomas

And these exact measurements are still saved in the txt. file individually?

---

No. The averaged samples are saved.

There's a fix in the latest version of the interface software for the TS USB where now the timestamp starts when you start the session. Instead of an absolute time-of-day, it's in milliseconds from the time the session was started. The 1st entry is at 0.30 seconds.

The Original interface software for the RS-232 Thoughtstream writes to the file 2 times/second but does not write a timestamp.

-Andy.

Quote:

---

Originally Posted by insk

Could it be, that my thoughtstream device is not the USB version, because I connect it with the PC by using a serial-to-usb adapter and not a common USB cable!

---

That is correct. The USB version has a USB connection on the console. You have the RS-232 version.

great. thanks. but i still don't know or can't figure out, how often the probe is written to the Txt file!

here a short excerpt of the txt file that has been produced by the thoughtsream:
1379
1382
1383
1383
1382
1382
1382
1384
1388
1349
1303
1246
1176
1091
1032
...

thank you :)

Ok, here's the confirmed info:

On the Original Thoughtstream (RS-232) the data sent out the RS-232 port and written to the .txt file is at 2 datum/sec or every 0.5 seconds.
The data output to the text file is only the ADC value.
To convert to probe resistance, use the forumula:

Probe Resistance (in MegOhms) = (1925 / (12 bit ADC value)) - 0.47

On the Thoughtstream USB the data sent out the USB port and written to the .txt file is at 3.33 datum/sec or every 0.3 seconds.
The data output is the ADC value and a timestamp.
To convert to probe resistance, use the formula:

Probe Resistance (in MegOhms) = (7700 / (14 bit ADC value)) - 0.47

Thank you very much for your help!