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pt104 output

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pt104 output

Postby Erik » Tue Jun 28, 2005 11:12 am

When I start converting from the pt104 unit what will the 5 bytes that the pt104 sends back to me contain?

The first byte contains the channel number and the measurement number.

The second byte is in msb.

What do byte 3-5 contain?

Best regards,
Erik
Erik
 

Postby Sarah » Wed Jun 29, 2005 8:16 am

Hi

Thank you for your post.

You can find full information on the bytes that the PT104 sends in the PT104 help manual under "Protocol Information".

Hope this helps

Best Regards
Sarah
 

Postby Erik » Thu Jun 30, 2005 11:36 am

Thank you.

One more question about the output when reading the temperature:

What does the manual mean when it says (p. 18 ) :

Code: Select all
2-5 reading data: byte 2 is msb
    0x20000000 = 0
    0xE0000000 = max


Should the number I get from the unit be subtracted with 0x20000000?
What is the max value reffering to?

Best regards,
Erik
Erik
 

Postby Sarah » Fri Jul 01, 2005 10:12 am

Hi

Thank you for your post.

What you need to do is cast 2 to 5 as a type long, but with byte 2 as the most significant byte (msb).

Hope this helps

Best Regards
Sarah
 

Postby Erik » Mon Jul 04, 2005 7:00 am

Thank you for your answer. But I still don't get it.

Code: Select all
    0x20000000 = 0
    0xE0000000 = max


What does this mean?
Erik
 

Postby Guest » Tue Jul 05, 2005 6:43 am

Why is this information only available in the pt104.hlp file and not in the manual?
Code: Select all
To calculate a resistance

Read the eeprom to obtain the calibration information for the channels

Take measurement 0, 1, 2 and 3 on a channel.

Then

result = (channel calibration * (measurement 3 - measurement 2)) / (measurement 1 - measurement 0)

To convert to a resistance divide result by 1000000.0


This would have saved me alot of time.

/Erik
Guest
 

pt104 output: meaning of the measurements?

Postby Flovic » Wed Jan 17, 2007 9:06 am

Hello,

I am busy writing a linux driver to read out temperatures from PT-100 3-wires. I am currently using the idea of the manual (ResistanceE6 = Calib*((Meas3-Meas2)/(Meas1-Meas0)), but I see an offset in the results for some sensors that is not present when using your Windows-driver.

What do the 4 measurements of each channel represent? According to the values I get, it doesn't seem to be the voltage of the 4 input pins, or am I mistaken...?

Why is there a possibility in your software to set "3-wires" or "4-wires"? What is the difference in your Windows-driver between setting "3-wires" or "4-wires"? Do you also use the (ResistanceE6 = Calib*((Meas3-Meas2)/(Meas1-Meas0))?

Thanks for your help,
Flovic
Flovic
 

Postby ziko » Mon Feb 12, 2007 3:02 pm

Hi and thank you for your post,

Please have a look at this link, this will answer all your problems.

http://www.picotech.com/support/viewtop ... highlight=

Kind regards
Ziko

Technical Specialist
ziko
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